VirtualPro

One of the things I’ve come to love about blogging is the fact that I occasionally get contacted by the odd tech start-up. Keen to demonstrate their latest market leading idea that is going to revolutionise the industry as we know it.  Earlier this month I was contacted by Mindy Anderson who is the Product director at tech start-up Virsto (short for Virtual Storage). Virsto had a new product for Microsoft Hyper-V that they wanted to demonstrate to me in advance of their big product launch. Having looked at Mindy’s background in the storage industry I was very keen to hear more about their new product.

The product is called Virsto One and is aimed solely at Windows 2008 R2 Hyper-V. The product introduces some new features like thin provisioned clones & snapshots, that expand the functionality of the standard Hyper-V product. The most interesting feature in my opinion though is the attempt to tackle the virtualisation / storage problem commonly known as the I/O blender effect.

So what does Virsto One look like?

The software itself installs in the parent partition of each Hyper-V host and consists of the filter driver, a system service and a VSS provider.  The filter driver sits above the raw storage (any block storage) and presents a VHD object to the parent partition.  This setup allows users to configure physical storage once and then use Virsto One to carry out all future provisioning tasks. This includes full support for creating  thin provisioned, high performing, cluster aware snapshots and clones from either the Virsto One Hyper-V MMC snap-in or Powershell.

So what about the I/O blender effect?

Most storage technologies are not designed for the virtual data centre, most are still designed around the one to one physical server to storage model. Think of a number of virtual machines all with predictable I/O behaviour (if you think of them as physical).  What tends to come out of the physical hypervisor host is a large amount of completely random I/O.  Random I/O has an obvious performance impact when compared with sequential I/O so as you increase the number of VM’s you increase the random I/O from your Hyper-V host.  So as VM density increases performance drops, as we all know low VM density is not your objective when you embark on a virtualisation project.

So Virsto One has an interesting way of dealing with this. Although the “secret sauce” has never been divulged in-depth in its basic form they journal the random I/O that comes down from the Hyper-V host to staging disk.  A staging area is required per physical Hyper-V host and about 20GB / 30GB of disk should support multi-terabyte write downs through use of de-dupe technology. Periodically the data in the staging disks will be flushed / written down to the primary storage location, at this point the Random I/O is laid down sequentially on primary storage to improve read performance. Virsto indicated that in time they would look to support multiple de-stages so that data could be de-staged to another array for business continuity purposes or to the cloud for disaster recovery purposes.

Are there any performance figures to back this up?

Performance figures from the Virsto test lab show the I/O Blender effect in full effect as VM density increases in the standard Microsoft setup.  With the Virsto software sitting in the middle, staging the data and de-staging it sequentially, there is an obvious improvement in performance.  These test results were from Virsto’s own lab and I stressed the importance of having these independently benchmarked by customers or an external consultancy.  Wendy indicated to me that this was something they were looking into,  I look forward to reading and sharing the whitepaper when it is eventually produced.

So who would be interested in a product like this?

Well ideally the product would benefit Hyper-V customers who require high density, high performing virtual environments.  Hosting companies making use of Hyper-V for selling virtual server instances may well see Virsto as a good way of increasing performance and reducing costs through the use of golden images, snapshots, etc.  Who knows though,  individual companies with an investment in Hyper-V may well see the benefit in this kind of product.  In a way I see it’s not to dissimilar to a company buying PowerPath/VE to increase I/O performance in a vSphere environment.

It is important to note that although this product has been initially built for Microsoft Hyper-V the principals behind it are hypervisor agnostic.  I asked the question “why Hyper-V?” at the start of my chat with Virsto,  the answer was that Hyper-V had functionality gaps and was easier to integrate into.  VMware on the other hand is a more mature product where VMFS has gone some way to deal with the traditional virtualisation storage problems.  Citrix virtualisation customers will be happy to hear that testing has already begun in the lab with a version of Virsto one for XenServer, ETA unknown at this stage.

So how much does all this cost?

At the time of the interview,  which was a good few weeks back the per socket price being talked about was $1,000 - $2,000 USD per socket, again not to dissimilar to the pricing for EMC PowerPath/VE.

Conclusion?

My impression at the time of the demo and interview was that this was an interesting product and very clever idea. The main selling point for me was the increase in performance, if it can be independently verified you would think the product will simply sell itself.  I look forward to hearing more about Virsto in the future and I am particularly interested to see what they can do for other hypervisors especially VMware vSphere with it’s new storage API’s.

Hyper-V, New Products, Storage hyper-v, Storage, Virsto

Over the last month or so I’ve had two invites to participate in vendor events abroad.  The first was an invite to the Gestalt IT tech day in San Francisco, the second was an invite to the EMC EMEA Customer Council event in Prague.  Now as much as I would love to go to everything I get invited to, I have a day job which pays the bills so in this instance I had to chose the one most relevant to my employer and that was the EMC EMEA Customer Council.

Having never been invited to an EMC Customer Council event before I wasn’t entirely sure what to expect. The basic structure of the event involved EMC sharing product roadmap and strategy, deep diving a few key technologies / strategies and then listening to customer feedback.  The sessions I attended were very interactive round table discussions, with a lot of enterprise customers who were not backward in coming forward with their feelings and opinions. As the sessions went on I started to see why EMC run these events. It would be hard to gain this kind of candid and honest feedback through any other medium, this kind of information is invaluable to a vendor. From my perspective as a customer I got a lot of good insight into roadmap, allowing me to more accurately propose a long term EMC storage strategy for my employer.  I also got to meet and chat to a lot of interesting people and best of all, I got to hear about the experiences of other customers. It was re-assuring to hear that whether you are an SMB IT operation or an enterprise level one, you tend to have very similar issues. The only difference sometimes being the scale of the infrastructure involved.

Now unfortunately unlike the Gestalt IT Tech Field day, the EMC Customer Council is governed by a non-disclosure agreement which means I cannot blog about any of the content discussed. However it’s a small price to pay when you get invited to an extremely well organised, well attended event where all parties involved get something out of it.

It’s easy to see why companies are starting to catch on to the benefits of engaging the customer community directly. In some instances the community becomes a self help group of sorts as well as an alternative marketing channel for a vendor. I often see “a community” leading the way with product information awareness, problem resolution, best practice and procurement advice. The VMware community stands as  one of the best examples of this,  there is a wealth of information out there and it’s not hard to find if you ever need to go looking. In fact if you use twitter or subscribe to an RSS feed like PlanetV12n more often than not the information lands in your lap without you needing to ever look for it.

I wanted to briefly cover off the Gestalt IT tech day. Stephen Foskett the organiser and chief recently set out on a mission to organise a technical field day that vendors would sponsor without the usual NDA’s being in place. Thus allowing the attending bloggers to write about what they saw until they couldn’t possibly write anymore.  He did an exceptional job and I believe the experience didn’t put him off, he’s already looking at organising Gestalt IT Tech Day 2.

Well the attending bloggers wrote post after post and there was lots of good stuff coming out from the vendor visits they participated in. This event is another good example of vendors engaging successfully with the community and everyone getting something out of it. The vendors get a chance to spread the word about their products and services and the bloggers get lots of technical content to put out there for their readers.  Everyone is a winner and that is exactly what a vendor event should be all about.

To read more about the Gestalt IT Tech day and sample some of the many articles written, click the link. What a Tech Field Day!

General, Gestalt-IT, Storage EMC Customer Council, GestaltIT Tech Field Day

I’m currently revising for an EMC exam and part of the course material involves doing some training on the Navisphere simulator. No problems, except where on earth do you download the simulator software? I searched for ages before finding out that you only get access to it on EMC PowerLink if you are an EMC employee, partner or you have bought the relevant training.  I had done the latter but still couldn’t get it downloaded for some reason,  that’s when a google search turned up a link to the following page which required no credentials, EMC Education Services product simulators.

I managed to download the latest version for EMC Flare release 28 without issue.  I was however asked for my EMC PowerLink credentials when I first opened the simulator so perhaps that’s how it’s authenticated against the training purchased. It’s a really good learning aid and I’ve been able to find out how to do things on it that I wouldn’t have dared to attempt on our actual CLARiiON implementation. Hope this link helps someone who’s searching for this,  took me ages to find it.

Certifications, Storage Certification, EMC, Navisphere

I’ve recently been evaluating some of the new features in VMware vSphere to see what use they would be to my current employer. One of the areas that I touched upon in my “what’s new in vSphere Storage”  blog post was thin provisioning.  I wanted to come back and cover this particular topic in more detail as it’s a key feature and it’s available throughout all versions of vSphere so I’m sure everyone will be interested in it.

What is Thin Provisioning?

Thin Provisioning in it’s simplest form is only using the disk space you need.  Traditionally with virtual machines if you create a 500GB virtual disk it will use 500GB of your VMFS datastore. With Thin Provisioning you can create a 500GB virtual disk, but if only 100GB is in use only 100GB of your VMFS datastore will be utilised. Credit to Chad Sakac for the diagrams below.

How does it work in vSphere?

Thin Provisioning is being heralded as something new with vSphere,  when in truth it was already available in VI3.  In VI3 creating a thin provisioned disk involved using vmkfstools and was also not a production supported VM configuration.  Now in vSphere the creation of thin provisioned disks can be carried out from the VI Client (see below) and is a supported production configuration for a VM.

It’s as simple as checking a check box, the results are pretty good to.  Below you can see I have created two thin provisioned VM’s on my new ESX4i host and you can see the provisioned space and the used space stats being shown in the VI Client. 

What are the benefits?

The thin provisioning  feature is perfect for my home lab environment where disk space is at a premium, but how does it translate into real world implementations of ESX.  Well I for one have been looking at exactly this to identify what benefits could be achieved within my employers ESX estate. A quick audit found that our development and system test ESX environment was running at 48% disk utilisation,  so straight away thin provisioning would save us 52% on storage capacity used. Paul Manning of VMware mentioned on a recent communities podcast that on average vSphere would save users 50% on storage.   This is possibly not such a big thing when your talking about test environments, but when you move up to production SAN Storage, saving 50% on an expensive SAN array is a very real and tangabile cost saving.  One that people should definately take into account when making a cost benefit case for buying or upgrading to vSphere.

What are the potential downsides?

One of my personal concerns with thin provisioning is the potential overhead on any write activity that would requires the extension of the VMDK file.  To me there is an obvious VMFS operation that needs to take place there which would add to the overall time to complete the disk write.  When there is a requirement to expand a disk, the VMDK files will increase in increments based on the block size of the underlying VMFS partition, 1MB, 2MB, 4MB or 8MB.  So the overhead may be smaller if your VMFS has been formatted with a bigger block size, i.e. for a 16MB write it only has to expand 2 blocks when the VMFS block size is 8MB but would have to expand 16 blocks if it was formatted with the 1MB block size.  I can imagine this percieved overhead could put people off using thin provisioned disks for certain production based environments, especially those where there is a lot of write I/O activity,  SQL Server or Exchange for example.  To counteract that though,  the improvements in the VMware I/O Stack should compensate for this performance overhead.  This could potentially leave you in a situation where you’ve reduced a VM’s storage footprint and still have performance equal to that experienced in VI3,  possibly not a bad trade off.  I’d also expect people running their VMware environment on enterprise SAN technologies from the likes of EMC or NetApp to notice minimal performance impact with thin provisioning as SAN memory caches help take up the strain.

Another downside is if you want to use VMware Fault Tolerance to protect a VM then you cannot use thin provisioned disks.  To be honest this is a small issue as Fault Tolerance protection is most likely going to be on virtual machines that are important to your organisation.  These machines are probably the ones you wouldn’t thin provision in the first place for performance reasons.

Thin provisioning creates it’s own unique problem in that what we’re basically doing here is over provisioning the storage.  You need to keep a very close eye on thin provisioning as it’s quite feasabile that your VMFS datastore could fill up and your virtual machines fall over.  Not what you want to come into on a Monday morning,  or any morning for that matter.  So you need to monitor your storage and ensure that there is enough free space.  One of the simplest ways to do this is through the use of the new alarms in vSphere that allow you to alert on datastore usage and datastore over provisioning.  These should keep you from filling a datastore and killing your VM’s or ESX Servers

One gotcha that you should watch out for is VM swap files, as these are usually stored with your virtual machines vmdk files in the VMFS datastore.  In VI3 the swap file was not deleted when a VM was powered down,  in vSphere the swap file is deleted on power down and recreated when the VM is powered up.  You should be aware of this when over provisioning storage as you could get into a situation whereby you find you can’t power on a VM because there isn’t enough space for the swap file to be created.  This becomes more likely as servers and VM configuration maximum’s increase,  if you have a VM with 20GB of RAM it’s going to need 20GB of disk space for the swap file.  if you have 256GB of RAM in your vSphere host and you allocate it all out to VM’s then you need to think about the 256GB of disk capacity required to service virtual machine swap files.

Storage vMotion

If you’ve already got a VI3 environment then the chances are that your VM’s aren’t thin provisioned,  how on earth are you going to take advantage of this new feature? Well if you have purchased a vSphere edition that supports storage vMotion then you can of course migrate the underlying storage and have it thin provisioned during the move.  This should allow existing VI3 customers to claim back a lot of space,  as I mentioned before I found that our development and test VI environments were only 48% utilised.  If I storage vmotion all those VM’s and thin provision at the same time I will free up about 1.5TB of storage that wasn’t being used in the first place.

I’ve included a video below which demonstrates the Storage vMotion and thin provisoning features in vSphere quite nicely, enjoy!

Gestalt-IT, Storage, VMware, vSphere Storage vMotion, Thin Provisioning, VSphere

This weekend I finally had the chance to catchup on some of the new storage features released as part of vSphere 4.0,  there are quite a few changes to cover,  some of them quite exciting.

VMFS Upgrade

Once of the good pieces of news to come out is that the VMFS changes in vSphere are minimal.  vSphere 4.0 introduces a minor point release (3.3.0 to 3.3.1) with some subtle changes,  so much so that it’s not really been documented anywhere.  Most of the changes with VMFS are actually delivered within the VMFS driver at the VMKernel level,  this is where most of the I/O improvements and features such as thin provisioning have been delivered as part of vSphere.

Upgrading VMFS was a major step in the upgrade from VMFS 2 to VMFS 3,  good to hear that there are no major drivers to upgrade VMFS as part of your vSphere upgrade.  Any new VMFS datastores created with the new vSphere hosts will of course be VMFS 3.3.1 however this is backwardly compatible with earlier versions of ESX 3.x.  If you really want to move onto the new version of VNFS, format some new datastores and use Storage vMotion to move your VM’s onto the new VMFS 3.3.1 datastores. 

Thin Provisioning

Thin provisioning is one of the areas that excites me most about the new vSphere release.  I conducted a very quick survey of my employers development and system test ESX environments recently and found that currently we were only utilising 48% of virtual storage that had been provisioned.  It’s easy to see where immediate savings can be made simply by implementing vSphere and thin provisioning.  I’ll be using that in the cost benefits case for sure!

Thin provisioning is nothing new,  it has been available at the array level for a while now, so one of the big questions is where should I thin provision?  Well that really depends what kind of environment you have I suppose.  Smaller customers will benefit greatly from VMware thin provisioning as they probably don’t own arrays capable of TP.  Bigger companies on the other hand might well benefit from carrying out both as they have both the skill sets and the equipment to full utilise it at both levels. 

Chad Sakac has written a superb article entitled “thin on thin where should you do thin provisioning vsphere 4.0 or array level” which goes deep into the new thin provisioning features and the discussions around what’s the best approach. I strongly suggest people give it a read,  it explains pretty much all you need to know.

Storage VMotion

The Storage vMotion in ESX 3.5 had a few limitations which vSphere addresses.  It’s now fully integrated with vCenter as opposed to being command line based in the previous version,  it allows for the moving of a VM between different storage types, i.e. FC, ISCSI or NFS.  One excellent usage of Storage vMotion is the ability to migrate your thick vm’s and change them to thin VM’s.  Perfect for reclaiming disk space and increasing utilisation without downtime, brilliant!
 
Storage vMotion has also been enhanced from an operational perspective. Previously storage vmotion involved taking a snapshot of a disk,  copying the parent disk to it’s new location and then taking the child snapshot and re-parenting the child disk with the parent.  This process required the 2 x the CPU and memory of the VM being migrated in order to ensure zero downtime.  In vSphere 4.0 Storage vMotion uses change block tracking and a process very similar to how vMotion deals with moving active memory between hosts.  The new Storage vMotion conducts an iterative process scanning what blocks have been changed, each iterative scan should result in smaller and smaller increments and when it gets down to a small enough size it conducts a very quick suspend / resume operation as opposed to using the doubling up resources method that it previously needed to.  Making it faster and more efficient than it was in it’s previous incarnation.

Para Virtualised SCSI

Para Virtualised SCSI (PVSCSI) is a new driver for I/O intensive virtual machines. VMware compare this to the vmxnet adapter,  which is an enhanced and optimised network driver providing higher performance.  PVSCSI is similar, it’s a specific driver that offers higher I/O throughput, lower latency and lower CPU utilisation within virtual machines. Figures discussed by Paul Manning on the recent Vmware community podcast included 92% increase in IOPS throughput and 40% decrease in latency when compared to the standard LSI / BUSLogic virtual driver.

A caveat of this technology is that the guest OS still has to boot from a non PVSCSI adapter (LSI / Buslogic),  you would look to add your PVSCSI adapter for your additional data virtual disks.  Currently only Windows 2003, Windows 2008 and RH Linux 5 have the software drivers to take adavantage of this new adapter.

Update  - Chad Sakac has posted a new EMCWorld I/O Performance comparison of the vSphere PVSCSI adpater vs the LSI SCSI adapter, check out the link for more details.

VMware Storage Book

Paul Manning mentioned on the recent podcast that VMware are planning a book dedicated to Virtualisation and storage in an attempt to consolidate the amount of documentation out there on Storage configuration and best practice.  Currently users need to look through 600 pages of the SAN Config guide and vendor guidelines. VMware would hope to try boil this down to a much more manageable 100 - 150 pages.

If you can’t wait that long, Chad Sakac has written the storage chapter in Scott Lowe’s new vSphere book which I believe is available for pre-order on Amazon

vSphere Storage WhitePaper

Paul Manning who I’ve mentioned in this blog post has written a great 10 page white paper explaining all of these features in more detail along with some of the more experimental features I haven’t mentioned. 

http://www.vmware.com/files/pdf/VMW_09Q1_WP_vSphereStorage_P10_R1.pdf

Gestalt-IT, New Products, Storage, VMware, vSphere esx, Storage, Storage vMotion, Thin Provisioning, VSphere

Was reading through my RSS feeds this morning while standing in line for a coffee (I love the iPhone) and came across Eric Sloof’s article on Compellent.

Compellent have introduced a powershell based command set to compliment their storage offering.  Now offering the ability to script a lot of the everyday CLI based tasks in a format that is becoming more and more popular.  For me the main benefit I can see is from an integration angle,  linking in windows and storage tasks together is the kind of thing that I can see becoming handy for BCP and DR scripting.

I had a small smile on my face when reading Eric’s article and I will tell you why,  I’ve recently been looking at Compellent for a solution I was building.  Compellent really impressed me with their offering, SAN simplified as far as I was concerned.  The fact that they started from scratch 4 years ago and heavily utilise software management, means that they’re not limited in the same way as some of the other legacy based vendors.  We didn’t end up choosing Compellent for the solution, however the choice was not based purely on the technical angle.  Compellent are still quite small in the UK but do seem to be making serious inroads into the market.  The awards they picked up this year are very impressive and I will be keeping an eye on their growth in the future.

The introduction of powershell to their offering I think shows what a good dynamic company they are. Be interested in any comments anyone has on working with Compellent or their solutions.

New Products, Storage, VI Toolkit / Powershell Compellent, SAN, Storage

Well I haven’t written anything in the last week or so as I appear to have been far to busy.  Luckily for me one of the reasons I was busy was down to the fact I was visiting Storage Expo in London.

I was there on official work business but as always I got the chance to indulge my unhealthy interest in all things virtual.  So what was the main theme doing the rounds at Storage Expo this year?  Well de-duplication appears to be the hottest topic of the moment.  Everyone is jumping on the band wagon and claiming to do it in some way or another,  I only heard about this technology about 9 months ago and now it seems to be spreading like wild fire.

I went to a talk by a technical architect from the Associated Press (Daily Mail, Evening Standard, etc) who had implemented a Data Domain DD580 appliance as a location to store his Vmware Snapshots / Backups.  He was getting a 20:1 and 25:1 de-duplication ratios and in some instances 60:1 ratio,  in fact it performed that well they were worried there was someting wrong with it when it didn’t fill up. They’ve since moved a number of backups off tape and on to this device quite successfully and over time the de-dup ratio climbs as there is more data on the device that’s duplicated.  How good is that,  you fill it with more data and the ratio goes up?!?!?  no wonder they’re valued at $1 Billion  It was summed up well at the end with a copy of an email from one of his storage team.

“to free up some space I deleted 22TB of old backups off a 5TB Data Domain storage device ??!?!?!”

A San administrator from CB Richard Ellis in the same talk had implemented a solution from FalconStor,  a company I had heard of but had not ever looked into.  He was getting 350:1 ratios on his file system backups,  unbelievable!! I couldn’t help thinking they must do a lot of contracts that have single word version changes or something because that is a crazy figure,  he certainly couldn’t explain why it was that high,  I wonder if FalconStor can.

I had a good chat with the guys at NetApp,  who interestingly enough are currently offering a guarantee (with some terms and conditions) that they can save you 50% on your storage usage for your virtual environment.  It’s all based on efficiency and some of it seems pretty sensible but neat at the same time,  however the disk setup the NetApp setup was being compared to in the presentation resembled a lesson in how not to setup your storage.  Won’t be to hard to gain 50% efficiency over something that wasn’t efficient in the first place.  However don’t get me wrong NetApp had some fantastic stuff going on in thin provisioning, SnapManager for Virtual Infrastructure and de-duplication,  I always have to stop and wonder though, how much is it all going to cost me???

I had a great chat with Sean from NetApp on the benefits of using NFS for Vmware,  now I’ve not had a lot of storage experience and it’s something I’m working on all the time to learn.  Sean took me through a whole load of stuff on the NetApp storage suite and how it complimented Vmware,  He used to do Vmware consultancy and it showed,  he knew his stuff and I have to say for 40 minutes we were scribbling on the whiteboard like mad, I learned a lot in that 40 minutes so thanks Sean.  Safe to say Im going to take a more indepth look at NFS for vmware and try learn a little more to see if it’s worth suggesting when we come to replace our VMware storage next.

Other highlights for me were meeting the guys from Compellent,  a company I’ve been following since VMworld 2007 and who seem to finally be getting a decent presence and excellent press in the UK. Their managing director Andy was buzzing,  so excitable and so energetic about the product,  it’s definately one I’ll be keeping a close eye on and was a worthy winner of a “best in show award” at VMworld 2008.

General, Storage