EMC World 2012 – Thoughts on preparing for a VDI deployment

We’re in the process of testing the deployment of VDI now so I attended a session about preparing for a deployment.   As I mentioned in my previous post, I’m not an expert on any subject after attending a one hour session, but I thought I’d share my thoughts.

The most important take away from the session was mentioned near the beginning – for a truly successful deployment you must do a detailed desktop IO analysis.  It’s important to have a firm grasp on the amount of desktop IO that your company requires and a detailed analysis is the only way to gather that info.   There are “rules of thumb” that can be followed ( 5 IOPs for light users, 10 IOPs for medium users, and 20 IOPs for heavy users), but you could easily end up either over-allocating or under-allocating without knowing the actual numbers.  Lakeside software and Liquidware labs were mentioned as vendors who provide software that does such an an analysis, however I’ve never heard of either of them and can provide no information or feedback on their services. There’s a good free VDI calculator available at http://myvirtualcloud.net/?page_id=1076.  Once you have a good grasp of the amount of IO you’ll need to support, scaling for the 95% percentile should be your target.

What’s the best way to prepare for VDI on a VNX array?  If you conclude from your analysis that your desktop environment is more read intensive, consider hosting it on storage pools that utilize FAST VP with EFD and FastCache.  Using VMWare’s View Storage Accelerator and EMC’s VFCache would also be of great benefit.  If your environment is more write intensive, focus on increasing the spindle count (even at the expense of wasted capacity).  All of the other items mentioned for read intensive environments still apply and would be beneficial.

Final thoughts:

– If you’re using Windows XP make sure disk alignment is set correctly.  If it’s not, you could see up to a 50% penalty in performance.

– Image optimization is very important.  Remove all unneeded services.

– Schedule your normal maintenance operations off hours.  Running patches and updates during business hours could cause the help desk phones to light up.

– Using NFS vs. block is a wash performance wise.  NFS is currently better for scaling up, however, as it allows for up to a 32 node cluster vs. only 8 for block (on linked clones).

– Desktops tend to be write heavy.  FAST VP is great!


EMC World 2012 – Thoughts on Isilon

I’m at EMC World in Las Vegas and I finished up my first full day at EMC World 2012 today.  There are about 15,000 attendees this year, which is much more than last year and it’s obvious. The crowds are huge and the Venetian is packed full.  Joe Tucci’s Keynote was amazing, the video screen behind Joe was longer than a football field and he took the time to point that out. 🙂  He went into detail about the past, present and future of IT and it was very interesting.

Many of the sessions I’m signed up for have non-disclosure agreements, so I can’t speak about some of the new things being announced or the sessions I’ve attended.  I’m trying to focus on learning about (and attending breakout sessions) about EMC technologies that we don’t currently use in my organization to broaden my scope of knowledge. There may be better solutions from EMC available than what the company I work for is currently using, and I want to learn about all the options available.

My first session today was about EMC’s Isilon product and I was excited to learn more about it. My only experience so far with EMC’s file based solutions is with legacy Celerra arrays and VNX File.  So, what’s the difference, and why would anyone choose to purchase an Isilon solution over simply adding a few data movers to their VNX? Why is Isilon better? Good Question. I attended an introductory level session but it was very informative.

I’m not going to pretend to be an expert after listening to a one hour session this morning, but here were my take-aways from it. Isilon, in a nutshell, is a much higher performance solution than VNX file. There are several different iterations of the platform available (S, X, and NL Series) all focused on specific customer needs.  One is for high transactional, IOPs intensive needs, another geared for capacity, and another geared for a balance (and a smaller budget). It uses the OneFS single filesystem (impressive by itself), which eliminates the standard abstraction layers of the filesystem, volume manager, and RAID types.  All of the disks use a single file system regardless of the total size.  The data is arranged in a fully symmetric cluster with data striped across all of the nodes.  The single, OneFS filesystem works regardless of the size of your filesystem – 18TB minimum all the way up to 15 PB.

Adding a new node to Isilon is seamless, it’s instantly added to the cluster (hence the term “Scale-out NAS” EMC has been touting throughout the conference).  You can add up to 144 nodes to a single Isilon array. It also features auto balancing, in that it will automatically rebalance data to the new node that was just added.  It can also remove data from a node and move it to a new one if you decide to decomission a node and replace it with a newer model. Need to replace that 4 year old isilon node with the old, low capacity disks? No problem. Another interesting item to node is how data is stored across the nodes. Isilon does not use a standard RAID model at all, it distributes data across the disks based on how much protection you decide you need.  You can decide as an administrator how the data is protected, choosing to keep as many copies of data as you want (at the expense of total available storage). The more duplicate copies of data you want to keep, the less total storage you have available for production use.  One great benefit of Isilon vs. VNX file is that rebuilds are much faster, as traditional RAID groups are dependant on the total IO available to the single drive being rebuilt, while Isilon rebuilds are spanned across the entire system. It could mean the differnce between a 12 hour single disk RAID5 rebuild vs. less than one hour on Isilon. Pretty cool stuff.

I only have experience with Celerra replicator, but it was also mentioned in the session that Isilon replications can go down to the specific folder level within a file system.  Very cool.  I can only do replications at the entire file system level on VNX file and Celerra right now. I don’t have any experience with that functionality yet, but it sounds very interesting.

There is a new upcoming version of the OneFS (called “Mavericks”) that will introduce even more new features, I’m not going to go into those as they may be part of the non-disclosure agreement.  Everything I’ve mentioned thus far is available currently.  Overall, I was very impressed with the Isilon architecture as compared to VNX file.  EMC claimed that they have the highest FS NAS throughput for any vendor with Isilon at 106GB/sec.  Again, very impressive.

I’ll make another update this week after attending a few more breakout sessions.  I’m also looking forward to learning more about Greenplum, the promise of improved performance through paralellism (using scale out archiceture on standard hardware) is also very interesting to me.  If anyone else is at EMC World this week, please comment!