Category: SMB

Now for the hard part – P2V Conversion

virtualization, P2V, V2V, hyperconvergence
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Ok, You’ve researched and spent the money and now you are the proud owner of a hyperconverged system.  Or any truly virtualized system, really.  If not, why not?  So how do I get all those physical servers into virtual servers, or what is commonly referred to as P2V conversion.

Well friend, pull up a chair and let’s discuss how to convert your systems.

There are three ways to get those physical boxes that now crowd your data closet and make it a hot noisy mess into a virtualized state.  Which method you chose will depend on several factors.  The three are not mutually exclusive, so feel free to use several of these P2V conversion methods in your environment depending on what the specific requirements are for each of your physical servers.

Rebuilding the Server

Rebuild the Server.  Over the course of time, and after around 4 dozen service pack updates, there is a lot of trash in a system.  Sometimes it is better just to start off fresh.  Using this method is best if you would like to update the underlying operating system, or if you are starting to have strange system behaviors.  This method is best for standard services like DNS, domain controllers, or application servers that you have clear ways to transfer just the data and configuration files.  A clean underlying install of the operating system and application services are a great way to breathe fresh life into an old, tired workhorse of a physical server.

Pros
  • That clean fresh feeling of a new OS install
  • Existing physical servers are up and functional while new server installation occurs
Cons
  • General installation and configuration issues
  • Time restraints – depending on how many servers you are building, well you are building new servers

P2V Utilities

Utilities.  There are as many utilities out there to manage P2V conversions as there are stars in the sky.  Everyone has their particular favorite.  In essence, these utilities make a disk image copy of your system and convert it to an ISO image, or even into virtual server disk formats.  It is the same concept as bare-metal restores.  These utilities make an exact copy of your application servers, so all the data and application files stay the same, but so do any strange behaviors that may exist within your Operating System.  If your server is operating well, this may be the choice for you.

Unfortunately, these utilities require that your server is off while making this copy.  So, plan for a long weekend while this gets done, and make sure that your users are aware that the IT department is closed for business while this happens.  So – this if probably not for those highly available services that NEED to be up all of the time.  Like your 911 systems or the servers that control ATMs.

Pros
  • Easy, guided conversion of disk images
  • Often converted directly to ISO image
  • Conversion often possible between virtual disk formats
Cons
  • Server MUST be offline to perform conversion operation
  • Time consuming
  • Application downtime
  • Freeware or inexpensive utilities may not have support contracts available

 

Dedicated High Availability or Replication Software

Dedicated software exists for those servers that need to be virtualized, but can’t be down for the hours that it may take to use the disk utilities that are discussed in the section above.  These utilities are pay-for, but fill a need not addressed by the disk image utilities.  These utilities often operate like a highly available failover pair.  What that means is agents are loaded on two servers, one that is physical and has the information you wish to virtualize – the “source”.  The other server is a virtual server with only an OS and the agent that will act as the “target”.

In this scenario, the utility makes a full “backup” from the source server to the target server.  Then changes propagate from the source to the target on a regularly scheduled basis.  When the cut-over occurs, the physical server goes down, and the virtual server comes up as an exact copy, often down to the same IP addressing.  This cutover can often happen in only minutes.

Pros
  • Less downtime for those critical servers
  • Exact copies of functional servers down to the minute
  • Support contracts are available
Cons
  • Often a pay for utility or service.  While this may not be an obstacle for IT shops, large numbers of servers mean large licensing fees
  • Often takes more time and better scheduling than other conversion utilities
  • Small period of time that services are unavailable while cutover occurs
  • Invasive – new agent software loaded on source and target servers

We have discussed the three ways that new hyperconvergence or virtualization shops can convert their physical servers to virtual servers.  Building new servers, using disk imaging utilities, and highly available utility agents all have pros and cons to address.  These three conversions move your physical servers to virtual servers and get you the benefits from virtualization.

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SSD – How much is too much?

Speed, SSD, fast, SAN, NAS
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I wrote an article just a few days ago entitled “Where did the 15k disk drive go?”  It was a short piece, quickly done and meant to draw fairly obvious conclusions.  When given a choice between faster and fastest, for the same or close money, people will always choose fastest.  Little did I suspect the sheer amount of comments and emails that I would get from that article.  It appears that everyone has an opinion on storage technology and how storage vendors build out their appliances.  So, in the spirit of keeping the discussion going, I’ve decided to ask the flip side of most of the comment and email subjects.  “If 15k drives are dead, then how much SSD is too much?”  Let the games begin!

How much SSD?

I heard a Texan once say “How much is too much?  Well, if it’s money in the bank or cows on the ranch, you can never have too much!”  He was talking about things that directly affected his performance as a cattleman and his ability to perform his job or company function.  The same can be said for SSD disk in the ever-changing storage arena of business.  How much is too much SSD in a storage array or on a server?  I’m not talking about the sheer amount of physical space – that depends on the applications and data depositories that the application will require.  Plus a little bit for growth.  What I am talking about is a percentage.  Of 100% of the storage space on a given server or storage appliance, just how what percentage should be SSD – fast but expensive?

In my opinion, much will depend on a storage study.  How many IOPs does your environment need so that storage is not the bottleneck in your environment?  Is there too much latency in your SAN or NAS?  If you don’t know the answers to these questions, then a storage study should be your next step.  Check out my article here.  SSD tends to be the most expensive option in GB/$, but that ratio is coming down as manufacturing processes change and get more efficient.  But we all work in the here-and-now, so as of today, how much SSD is too much in your SAN, NAS, or hyperconverged appliance?

All Flash, or no Flash?

I have seen several examples of SSD ratios, all aided by software in one form or another.  These fall into two camps at either end of the spectrum.

To start, there is the storage appliances with no SSD.  These are fairly simple, and I don’t see them around much. If all you need is an array of large disks spinning merrily along, and your storage goals are met, do you really need SSD?  I have been in proof-of-concept trials where SSD would not make any difference is system performance, until the programmers changed the application code to make it more parallel.

Then there is the “all flash all-the-time” argument.  I am familiar with one storage array vendor that sells an all flash array with compression and de-duplication and claims that across the environment, the cost per used Gigabyte is cheaper than their hybrid array (which does not offer any compression type functionality).  Of course with de-duplication your milage may vary, but that makes a compelling argument for all flash.  There are certain industries where milliseconds matter, like stock market trading, or transaction processing.  Those industries go all flash without a second thought.

The middle ground?

So now we reach the middle ground, where the argument get heated.  Hybrid arrays replace the fastest tier of storage with SSD, or use large amounts of SSD as caches to buffer regular hard drives.  Manufacturers use SSD to take the place of those good ol’ 15K drives, as well as some of the 10k drives, too.  The larger and slower SATA drives remain the workhorses for storage.  Older, slower data goes there to die.  Or at least drive your backup software crazy.

So, where does all this leave us?  Should we go ahead and use all flash since it is the wave of the future?  Since I will be replacing my array as I outgrow it, should I buy affordable now, and look to put in all-flash when it is the standard?  Assuming that I am not a government agency with black-budget trillions to spend, how much SSD is too much SSD?  Looking forward to your comments.

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Where did the 15K disk drive go?

15k disk
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Just a few years ago, everyone wanted disk drives that spun at 15,000 rpm, commonly known as “15k disk”.  Why did people want these?  Well, the faster the spindle turned, the shorter the seek times, the less latency and the faster the writes to that disk.  Since I never worked at any of the drive manufacturers, I can’t really speak to the truth of this, but I do take it on faith.  So when everything on a storage array was spinning disk, why did people want “15k spindles” in the line up?  And since SSD has become so popular, why don’t I really see them anymore?

Why do I want expensive, small disks?

The reason that everyone wanted 15k disk drives was pretty straightforward.  The disk themselves were fairly small in capacity (600GB being a standard size) and expensive on a GB/$ ratio.  But they were FAST.  If there was a target IOPs for a storage array, it was easier to balance out size and speed with a ratio of 15k disk, 10k disk, and standard 7.2k SATA drives.  Speed from the smaller drives and space from the slower drives.  While everything was acceptable ON AVERAGE, the laws of physics still applied to the different speeds of disk. There was a bit of balance that had to happen. You could put your fast access volumes on 15k, but you still needed the SATA drives for the larger storage requirements.  This solution worked, but was expensive – and a bit “hands-on”.

There were even a few manufacturers that started to offer ILM with these systems.  This means that “hot” or active data writes to the 15k disk drives since theoretically the write speed on these is fastest.  Your storage appliance now writes more across the aggregate of your SAN environment.  Once this data is written to the fastest disk on your SAN or NAS, it stays there for a bit.  This logic being that it also has the fastest read times and therefore the best performance when you wanted to recall that data.  These ILM vendors then move the data off of the fastest tier of disk to a slower tier as that data becomes less active or “ages”.  This allowed you to store older, less accessed data on the slower and less expensive tiers of storage.  Because the database has to run quickly, but who cares if it takes accounting a week to get the data for their year-end reporting, right?  Remember that the next time you need that expense report reimbursed!

The next step

Then SSD entered the market.  At an affordable price, that is.  Not only could manufacturers use SSD as caching, but they were large enough that manufacturers could also use them as the fastest tier of data storage in an ILM strategy.  And the form factor of SSD disks allows them to be used in the existing storage appliance enclosures – JUST LIKE spinning disk.  Now, instead of expensive 15k disks, you could put in units in the same form factor that would read and write several hundred times faster than disk.  With the speed and storage capability of SSD, it became unnecessary to use 15K disk in storage appliances for speed.

But I still see some 15k disk out there…

You will still see 15k disk used in local solutions.  A 15K SAS disk RAID 5 array is quite speedy when used in a local physical server.  Virtualization solutions, or database servers will often use 15K spindles for disk targets.  They need sizable storage capacities and quick access.  However, the cost of SSD is coming down.  This allows the justification for installation of SSD disk or arrays in physical servers.  Seagate has stopped development of new models for their 15k disk.  Previously storage technology leapt from Tape to HDD for large data storage like disaster recovery.  Now storage acceptance from high speed disk to SSD will likely accelerate.  Technology to increase access speed, reduce manufacturer costs, and increase storage capacity will accelerate this change.  So long 15k disk, we hardly knew ya!

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The SMB IT Guy’s guide to ensuring your success from Hyperconvergence.

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By now, everyone realizes the advantages of server virtualization. Flexibility in the face of rapidly changing technology, reduction in administrative effort on busy IT staff, and cost savings from reducing physical machines is just the beginning. As you may have heard, hyperconverged infrastructure solutions offer all of these advantages, plus the added benefit of simplicity in your environment.

This article is targeted towards small to mid-sized business: 50 to 500 employees supported with 1-5 or so staffers in the IT department. These IT shops don’t rely on specialists, but a few really good “jack-of-all-trades”.  If you are looking for a way to bring this up with the boss, make sure to see the article written for the senior directors or owners in the business here.

So – there are a lot of different hyperconverged vendors out there and a lot of solutions. If you believe the literature and web demos, they will all do everything you need in your environment. How do you know which is the best and what to look out for?

As with everything in life, the answer is – It depends. No one can answer the question of which is best for you, without the intimate knowledge of your environment which probably only you have. What I can do is provide you with some questions that you might want to ask the various solutions providers. These may help you determine which solution works best for your organization, and that management will buy off on.

Here are 5 questions to help you in your inquiry.

What comes in the box?

Well, not literally, but what does this solution entail? How many servers of MINE will this solution cover, and how much extra capacity will I have? Are there any extras that might later cost me money or maintenance fees? Are installation services needed and possibly included in this solution? Is high availability between hardware units included in this quote? The answers to these questions may not make or break the solution for you, but you should know what you are getting for your money. You need to be able to present this effectively to management so no one gets any unpleasant surprises later. Maybe you only need a barebones system right now. That’s fine, but make sure that you know what is included and what everyone’s expectations are.

Licenses

There are a few main solutions out there and they all handle this differently. Many manufacturers of these solutions OEM hypervisors, so ask how that affects the cost of your unit(s). Is there the possibility of having to purchase additional software licenses in order to expand? Are all of the management consoles and utilities provided under the license of the hyperconverged product? If not, what isn’t included that I may want, and where can I get it? Do I need to deal with the hyperconverged manufacturer, or do I have to drag another vendor into this? How many vendors are involved in this solution and who do I call if I need support? Are there different tiers in the number of licenses? What do my maintenance costs look like 3 and 5 years out? If my server count grows by 20% per year, what additional costs will I encounter? Most solutions providers will be more than happy to work these numbers for you, and your management will love your forward thinking “strategic planning”.

Simplicity and Ease of Use

Hyperconverged infrastructure solutions are all about making things simple, right? Find out. Get to know how this particular solution works. You don’t need to see the actual code, but it might be nice to know conceptually how everything fits together. Does this solution come with any training? Is training required? Is training an extra cost? Are basic functions like setting up virtual machines, virtual disks, and virtual NICs intuitive? What about more advanced tasks? That pesky application that we have that demands VLAN tagging, how does this solution support that? Can I do every task I need to do from the management interface? How easy is this product to use for non-pre-sales-engineers-that-don’t-work-for-the-manufacturer?

Backup, Recovery, and Failover

OK – we are looking at this solution because recovery and business continuity are supposedly made much easier with this. Can I stop dropping by the office after hours and on weekends to do silly little server tasks, like rebooting crashed boxes… for payroll… at the end of the month? How does this solution help me with recovery tasks? How does it handle a crashed server? How does the solution handle network failures, disk failures, or whole server failures? Can I SEE it demonstrated live? How will this solution affect my existing backup strategy? Will my current backup solution work, or does this solution include something that replaces it? Does it do native snapshots? How many? Will it replicate those snapshots somewhere automagically? How can my existing DR plan be improved with this solution?

Scalability

Everyone has a constantly changing environment. How does this solution handle growth and changing needs? What does it take to add 20% capacity to this solution? How much does it cost, and how easy is it to do? Will I have to stop production or do it at 3am? Do I need additional chassis to do this, or can I upgrade the units internally? Will this require downtime? What if I want to start moving things to the edge of my infrastructure? How flexible is this product? Do I have the ability to add more memory, CPU, or plain disk to this solution independent of purchasing the next model? What is the roadmap for this product line – Flash disk, software, and NIC speeds?

Hyperconverged infrastructure promises to be an amazing step in the IT virtualization lifecycle. There are different capabilities and features in all of the various solutions. You just need to ask a few questions to figure out which one is right for you. Not just right for you right now, but right for you in 3 to 5 years. Only after you can answer the questions above will you be able to enjoy the REAL benefits of simplicity that hyperconvergence provides.

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The SMB Owner’s Guide to Ensuring Your Success with Hyperconvergence.

SMB manager owner CIO executive
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Hyperconvergence is the newest IT architecture that is removing both cost and complexity from virtualization infrastructure. This article assumes you are aware of the advantages of hyperconvergence and how it applies to the business end of your small to medium business. What we are going to discuss is how to ensure that you are getting the TRUE advantages from Hyperconvergence over what all those fancy marketing papers say you can.

A small to medium business(SMB) doesn’t mean just a tiny kiosk in the mall that only has a single POS computer. We’re talking about SMB in terms of between 50 to 500 employees with an IT staff of up to 5 full or part-time staffers.

There are a lot of claims out there around hyperconvergence technologies. At the top of the list is reducing costs. Also, it claims to be a simpler environment for your IT staff – increasing productivity. As the business owner, what questions do you need to ask to ensure that your hard-earned capital is well spent?

Among all the claims, there are 5 things that you need to look for in a hyperconverged solution to ensure that your solution brings everything to your business that it can.

Vendors in the solution

One of the claims of hyperconvergence is simplification of the solution. This is potentially achieved by eliminating the multitude of vendors that are part of a traditional virtualized solution. This solution involves how many vendors? Where do the individual responsibilities of each vendor start and stop? Will you need multiple support contracts, or is everything covered under one master contract? Is there a central support number to call, or is there the possibility of finger-pointing between various manufacturers? In this vein, is the solution the intellectual property of one company, or are there different licensing agreements in place? How could this affect YOUR investment in the event of a manufacturer bankruptcy?

Licensing

The initial install of the solution is probably correctly sized for your business. What happens if you need to expand that installation? If you need more virtual servers, or to add more users, are there going to be any additional license fees (Vmware)? What about yearly maintenance fees, will those grow, too? What if we expand and I want to add virtual servers at another location? Are my licenses “tiered” or do they get more expensive for additional functionality or when I hit a certain license count? These are not necessarily deal-breakers, but fore-warned is fore-armed. It sure helps to have a reliable idea of licensing costs when budget time rolls around.

Expandability

Hyperconverged solutions come in all shapes and sizes. Different solutions exist for a dozen virtualized servers, and for several hundred virtual servers. Whichever you have is not as important as the answer to the question Is the solution expandable? Does the solution have the ability to cover your business as it grows, without the dreaded “fork-lift upgrade”, which means downtime for the profit-centers of your business. In addition to this, if upgrades are possible, do they involve downtime?  Can your sales department sell while the upgrades occur?

Installation

Sure, everyone will be more than happy to install this beast once you have signed on the dotted line, but just how complex is that installation? Can we operate on the existing systems and minimize downtime while the installation occurs? How complex is the switchover to the new systems (Easily migrating VMs or data)? Can your IT staff shadow the installation? Is it easy enough that they can do it themselves with just a bit of guidance?  Can your staff expand the system, or will you need outside help?

Ease of Use

Now that we have it and everything is running, just how difficult is it to get my IT staff up to speed on the product? Is there additional training that will take my staff off site in order to learn how to use this product? Once I train my staff, am I in danger of losing them to a competitor willing to pay more for those certifications? When we add additional virtual servers to the environment, will my staff be able to do that? How difficult is it, and how long will it take? Since my staff isn’t as large as some of the big-guys, how difficult is it to cross-train?

Summary

Hyperconvergence is an amazing leap forward for IT virtualization. Correctly sized, designed, and implemented it promises a lot to the small to medium business. But like most things in life, one size doesn’t necessarily fit all. Spending money wisely requires due diligence. Make sure the business squeezes all of the value that you paid for from this solution. Address the questions around vendors, licensing, systems expandability, installation and ease of use.

Engage with the manufacturers and ask the solutions provider the next step questions addressed in this article. This will ensure that you enjoy the advantages advertised while getting the exact solution to benefit your business NOW.

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How Do I connect to my Storage Appliance?

Fiber Channel attached Storage Appliance
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In this article, we are examining the third question asked in our original article The Beginners Guide to what to know before you shop for a Storage Appliance.  That question in a nutshell is “How do I intend to connect my storage so that all of my applications can get to it?”  Well, that question begs a good look at your current environment.  Based on what you find, we will determine if you should connect to your existing environment or connect through other dedicated technologies within your existing environment.  There are also other less common methods to connect to your storage.

Using Existing network infrastructure

Is your network stable?  Every network administrator or sysadmin knows who the problem children are in their network.  Do you have any segments or switches in your environment that are currently congested or causing delays now?  Adding storage to it will only exacerbate the problem.  On the flip side of that coin, a well-running network makes adding storage easy and inexpensive.

In addition, the speed of your existing network will come into play.  Depending on your current storage needs, I would recommend that no one attach storage at speeds of less than 1 Gigabit Ethernet. As 10 GigE becomes more affordable and more pervasive in networks, it is never a bad idea to increase bandwidth to your storage.  Fortunately, many manufacturers enable upgrading with field replaceable units.  Speak with the vendor about this ability in the units you are investigating.

Most storage appliances will support a variety of connection protocols.  For storage area networks (SAN), it is important that iSCSI be supported in the unit.  iSCSI will support most of the externally mounted volumes or LUNs (Logical Unit Number).  For Network Attached Storage (NAS), NFS is a popular way of attaching storage for most virtualization shared storage and *nix computing.  These storage protocols may all be supported, or only some of them.  SMB/CIFS should be supported for full functionality in a Microsoft network.

Using Dedicated connection technologies

There are situations where the use of the existing network may not be advisable.  If the network is older or slow, putting the data needs of shared storage on the network will just exacerbate an already slow situation.  In this case, there are dedicated connection technologies that may come to the rescue.

Ethernet connectivity is still a very viable alternative, using dedicated switches and VLANs.  VLANs are Virtual Local Area Networks that allow for the logical partitioning of ports within a switch to create virtual switches and LANs.  This lets you segregate data traffic and dedicate resources to the various ports that may be passing your data traffic.

Fiber Channel (FC) is a mature, well established connection technology.  FC uses glass fibers to connect physical servers to physical storage using light.  While this technology is a bit more expensive than traditional ethernet switches it does have advantages over ethernet.  There is tremendous support for this protocol in software and hardware because it is a very stable protocol developed specifically for storage.  Fiber Channel allows for data to be consistently delivered with very low overhead.  Fiber Channel switches are available to connect servers to storage in a logical mesh setup, but it is also a regular practice to directly connect servers with FC Host Bus Adapters (HBA’s – think of an HBA as a fiber channel version of a network card).  This will cut out the expense of a Fiber Channel switch for smaller deployments.

Exotic Connection methods

In addition to the well established protocols of Fiber Channel and iSCSI, there are other ways to connect storage.  There are storage appliances out there that will allow connection to servers via specialized technologies like InfiniBand, or SAS ports.  There is eSATA that is available.  These various ways to connect range from the super fast (InfiniBand – and expensive by the way) to the fairly common and slow.  “Exotic” connection technologies serve special cases and are outside the scope of this article.  These connection technologies will limit your field of vendors, but not disqualify you from a storage appliance.

Considerations of Connectivity

In addition to the connection methods discussed above, there are also other connectivity possibilities to consider.  Bonded connections is one.  Bonded connections make multiple physical paths (read cables or ports) to appear as one logical path to data.  In essence, two 1GB Ethernet connections becomes one logical 2 GB Ethernet connection.  A single path of bandwidth to the storage appliance will be quickly overwhelmed.  There will be many servers and users trying to connect to the storage.  Bonding allows several ports to simultaneously send out data.  Bonding also helps with failover.

Another consideration of connectivity is failover.  Although it may not happen often, if a cable, NIC, or port fails on the storage appliance or on the connectivity side, all servers using that storage are suddenly unable to access data.  Or all of your virtual machines may come down at once.  You have placed all of your proverbial eggs in that one proverbial basket.  Failover mitigates this risk accordingly.

This is often accomplished through the use of different controllers or “heads”.  Two (or more) controllers allows for multiple disparate paths to the data.  It allows for one head to crash and you still have access to your data.  It allows for one power supply to fail, and you still have access to your data.  Many manufacturers will vary on how they support this functionality, so it is important to research this carefully.  Make sure that the storage appliance will run on one power supply.  Verify that the controller heads support failover.  Implement bonded connections.

Summary

In this article, we have discussed the final question raised in our original article about finding the best storage appliance for your environment.  We have gone over considerations of attaching the shared storage to your existing network, the prospect of attaching the NAS or SAN via new connectivity, or even attaching via a special, non-standard or exotic connectivity mode.  Many vendors support these differing connectivity methods.  Specialized connectivity will limit the number of storage appliances that you have to choose from. Most users know that they are required from the start and can plan accordingly.

 

 

 

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How Will I use my Storage Appliance?

Servers and Applications attached to storage appliance
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We previously discussed doing a storage study for your environment.  This article continues after you’ve done that study and have those numbers to help you in determining what you need in a storage appliance.  In this article we will go into the use scenario for your environment.  In essence, “How will you use this storage appliance?”  What applications will be attached and how many users will be on these applications?  How will that affect what I need in a storage appliance?  This article is designed as a starting point for the novice user, not the storage expert.  It will make you ask the right questions for your environment so that you can find the right answers to get the best solutions for your needs.

So, to determine how we will use this appliance, we need to take stock of our environment.  Don’t worry, this is not as in depth as the storage study.  As a matter of fact, you probably already know most of this information just from administering your environment.  It is just a matter of collecting all of this information in one place and using it to project how you are currently using your environment, and how you plan to use a storage appliance in the future.

Numbers of servers, applications, and users.

Probably the single most important consideration of the storage environment is how many.  This applies to how many servers, applications, and users will be regularly using this storage.  Of course, a storage appliance that regularly supplies data to hundreds of users will have different speed and space requirements than appliances that may be used by only a few users.  The Google and Facebook storage environments will amaze you.  So to start, we need a pretty good estimate of how many physical and/or virtual servers may be attaching to this storage and how many users will be accessing data on it as well.

It stands to reason that a mail server that is supporting a large company will need more storage resources than a server that is supporting a dozen.  More users means more space and more speed.  This should spill over into every aspect of your environment.  The larger applications with more users will need more speed and probably more space.

If all of your applications are inward facing, then your work on this part is almost done.  Many companies, however, also host data or applications for outside users as part of their business model.  Maybe it is as simple as an ordering system that a few trusted customers are allowed access to, or it might be as complicated as you company hosting data as your business model.  Either way, it is important to count outside customers in the numbers that you will use to determine storage requirements.  And those customers may be the most important of any that you have.

Future Growth

Also important, although it is not our primary concern, is future growth.  This includes anything that will grow the amount of storage, like acquisitions.  The current space and number of users will tell us where our storage appliance needs to be NOW.  Several items in the storage study will show us how large we are growing with current users and applications.  Future growth of employees and business units will give us a look into how much larger we may need to grow outside of our regular growth numbers.  Because almost nothing gets smaller, right?

What applications are you using?

The type of application that you plan to run in conjunction with your storage appliance matters, and there are two primary types of access.  The speed of access is important to applications like databases.  The amount of storage is important to applications like file shares and home directories.  Please note that these two types of applications are NOT mutually exclusive.  Traditional applications will use a combination of both.  A pure inventory database is probably running very lean and wants speed.  Especially if it is serving records out to multiple sites or users.  I have never met a DBA that doesn’t want more speed and then even more.  But that database may reference a document imaging system that contains large files.  Or it may have BLOBs inside of it.  These things will increase the amount of space needed, but also require that objects be accessible in a reasonable amount of time.

Do a site survey of the applications and their types in your environment.  It is important to keep in mind that databases are everywhere.  In the traditional applications, but also in your mail application.  In special applications that may be specific in your business.  And CERTAINLY in most business intelligence applications that management may be using.

Is or will virtualization be in this environment?

You may be using virtualization in your environment and are looking to add shared storage.  Or you may be looking to virtualize and want to “do it right” by adding a storage appliance right off the bat.  Neither way is wrong and both can apply to this decision.  A well done storage study includes either the servers that are already virtualized or the servers that you will virtualize.

As a small aside, remember that Aristotle said “Nature abhors a vacuum”.  This is how it applies to you. Only the physically unique servers will not be virtualized once you see how great virtualization is.  I refer to servers with physical hardware that cannot be virtualized.  Like a fax server with special cards, or a huge database server that is clustered for performance or availability.

I mentioned storage space above, and that is an important consideration.  Virtualization makes your physical environment much more efficient.  With additional storage space, there is always the temptation to build more.  More servers, more drives, more home directories with cute downloaded pictures of kittens and recipes.  This is not an “if” question, it will happen.  Since you are virtualized, every manager’s wish list of applications comes true.

VDI

In addition to virtualization of servers, there is always the virtualization of desktops, laptops, and portals. The end users in your business.  VDI is an extension of server virtualization technologies and is making serious inroads into businesses large and small. The advantages make it easy to see why.  While planning actual storage requirements for VDI is outside the scope of this document, it is a consideration.  If you are planning to add VDI into your environment, then now is the time to start planning.  You will need a fair amount of capacity and speed depending on the number of users you plan to support.

If you are not planning to add it right now, then at least consider the ramifications that it could have to your storage environment.  New storage appliances are usually a significant purchase.  Plan on how to expand space and speed capacity on the unit you wish.

Summary

In a previous article, we discussed things that you should look for before deciding on a storage appliance that is applicable for your environment.  In this article, we went over the second of the information gathering exercises – How you intend to use your appliance.  What your current environment entails as far as users and applications, how those applications access data, and the presence of virtualization or VDI in your environment are all important questions to answer.  In the next article, we will look at how best to connect your storage appliance to your existing network.  Do we use existing infrastructure, or will we be adding the newest and fastest tech out there?  Tune in next week!

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The Storage Study – or How do I determine what my environment is using?

Storage Study
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In a previous article, we discussed three important questions to answer about YOUR environment before jumping into a storage appliance.  In this article, we will delve deeper into the first question we asked, “How fast and how much storage do you need?”.  This article is designed for the IT generalist, someone who is looking for some insight on how to do one.

So – how do I tell what I need?  The first step is to do a storage study.  The storage study is done in your environment for a period of around seven days.  Why seven days?  Because that will capture an entire work week of your environment.  And by work week, I mean those weekends that systems guys work and backups run on as well.  Is Saturday a full-backup day?  You want to see what the impact is on your systems.  Perhaps accounting prepares reports for payroll on Wednesdays.  Usually, a seven day sampling of your storage needs will account for standard practices within your environment, and not create information stores that are massive in size.

If you would like to capture more days than seven, break it out into multiple capture files of seven days.  Perhaps doing multiple sampling weeks during significant system events would reveal more details about your environment.  End of the quarter accounting processing?  Start of a new production cycle?  You decide.

The storage study should include several important take-aways collated and also broken out by host or server.  These four important metrics are IOP/s, Latency, Storage Footprint, and information on new (or “hot”) data.  We will delve a bit deeper into what each of these means below.

Input/output OPerations per Second (IOP/s)

What is an IOP, and what does it mean to my environment?  IOP/s simply put are a measurement of how many storage operations your host is doing every second.  IOP/s can be misleading, though.  While a single read operation generally takes 1 IOP, writes to disk can use up to 6 IOP/s for the same bit of information.  Why this happens is a bit technical, so your relevant question should be “How do I account for this?”

In addition to the overall IOP/s number, most studies will include a read vs. write percentage. This is usually written as 65/35, or 65% reads across this study and 35% writes.  This percentage determines how exactly to account for the IOP/s that were collected.  Of primary importance to the IOP/s study, though is the IOP/s over time.  This will help determine when the busy parts of the day are.  You should see numbers for absolute peak (meaning that this was the largest IOP/s event during the entire sampling period), and several percentiles.

The 85th percentile number is what is usually used to determine how to size your system.  You can certainly size your system to accommodate your peak IOP/s, but usually this is more appliance than you really need.  It follows the same logic of building a house that is above a 500 year flood plain.  Sure, your house won’t get flooded out (statistically speaking) for 500 years, but will the house even be standing by then?

Latency

OK – we know about how many IOP/s our systems are using in the course of our storage study.  Now, how long is it taking those IOP/s to be serviced?  In essence, your systems are issuing commands to your storage, but how long does it take your storage to complete the command?  Is that number acceptable?  Milliseconds are the usual time.  Lower is better.

Peak and trending latency are important.  If peak latency reaches 100ms, there is cause to investigate further.  Most applications are tolerant of high latency.  High latency is noticed in database record access times, or the spinning wheel/hourglass of uncommitted data.  It can be a bit tricky to run down exactly where the slowdown may be occurring.  Our primary concern with this storage study is that it is NOT happening along the disk I/O path.  Common culprits are slower disks, inadequate system RAM, and older CPUs.

If you start to see this number trending up or if you see spikes during the day, this is indicative of concerns in your system. While your disk storage may not be the bottleneck, we would like to be able to disqualify it.  Your planned storage appliance should be sized to accommodate any extra load.

Overall Storage footprint

Overall footprint is straightforward.  How much stuff do you have stored on all of your systems?  You will see this represented both by the server and also the entire environment that you collected.  This is often represented by a total amount of space in the environment – all the space on all the hard drives.  The amount of used v. free space is important.  This lets you know how much of all the spinning disks that you are have filled with your data.  A small amount of data on a fast, expensive disk or disks is not cost effective.

If you conduct multiple storage studies, compare the amount of used space from one study to another. This will give you an idea of how quickly your environment is growing.  Most of the storage study tools out there will collect information on each disk individually.  This allows you to drill down to the application level.  Find those greedy disk hogging applications quickly.

This metric will help you to determine how much overall space you should put into your storage appliance.

“Hot Data”

Hot data is data that is accessed, changed, or newly written by your systems within the storage study collection period.  In essence, this is the data that your applications used during the study.  All other data is not accessed, touched, or read during this time, but may be necessary to keep.  This hot data contains clues into how much your overall data needs may be growing every week.

Hot Data also answers the question of how fast your storage needs to be.  Writing data puts more of a strain on a system than reading data.  Hence, we need a faster system the more writing we do.  Hot data also gives us a rough estimate of what new data was written on the system.  This allows us to extrapolate what your storage needs will look like in a quarter or a year given your current rate of growth.

One important aspect that hot data drives is the speed of the storage appliance.  The higher the percentage of hot data the faster the storage appliance needs to be.  The larger the overall amount of hot data, the faster the storage appliance needs to be.  These are important considerations in correctly sizing storage appliances for both size and speed.

Accurate growth rates allow us to properly size the overall storage capacity of a storage appliance.  No one wants to buy too little space right off the bat.  But it is also pertinent that we not buy too much storage at the onset of the project.  Storage prices go down every year as capacity goes up.  It is financially cheaper to only buy the storage when you need it, not buy it all up front.

Summary

A storage study is the first step in determining your needs in a storage appliance.  This report generates many of the metrics that are required to correctly size a storage appliance.  The numbers generated will give us ideas of how much disk space overall we need, and how fast that disk space needs to be.

We have discussed IOP/s, Latency, Storage Footprint, and information on new (or “hot”) data in this article.  Once you have collected these metrics, analyze them.  Next, let’s see how various applications affect our storage needs.

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