To recap, below you will find the previous articles:

• ThinIO facts and figures, Part 1: VDI and Ram caching.
• ThinIO facts and figures, Part 2: The Bootstorm chestnut.

Off topic note:

two years ago at an E2EVC event, the concept behind ThinIO was born with just a mad scientist idea amongst peers.

If you are lucky enough to be attending E2EVC this weekend, David and I will be there presenting ThinIO and maybe, just maybe there will be an announcement. Our session is on Saturday at 15:30 so pop by, you won’t be disappointed.

Back on topic:

So here’s a really interesting blog post. Remote Desktop Services (XenApp / XenDesktop hosted shared) or whatever you like to call it. RDS really presents a fun caching platform for us, as it allows us to deal with a much higher IO volume and achieve deeper savings.

We’ve really tested the heck out of this platform for how we perform on Microsoft RDS, Horizon View RDS integration and Citrix XenSplitPersonality with Machine Creation Services.

The figures we are sharing today are based on the following configuration and load test:

• Citrix XenDesktop 7.6
• Windows Server 2012 r2
• Citrix User Profile Manager.
• 16gb of Ram.
• 4 vCpu.
• LoginVSI 4.1 medium workload 1 hour test.
• 10 users.
• VMFS 5 volume.

Fun figures!

Diving straight in, lets start by looking at the volume of savings across three cache types.

Reviewing the details for a moment:

Running repetitive tests of at least 3 per cache type, we found even at the lowest entry point we would support (50mb per user) we saw phenomenal savings of over 70% on write IO.

No pressure no diamonds!

To put that into perspective, at a 512 MB cache for 10 users, our cache reached maximum capacity at the second user login. With 8 users still left to login, cache full and still an hours worth of load testing left, our ThinIO technology was under serious pressure.

This is key to why ThinIO is such a great solution. We won’t just perform great until we fill our cache, we don’t require architecture changes or care about your storage type, we have no lead times or install days, we will carry on to work with what is available to use, to take a large ammount of pressure off storage IOPS and data throughput.

With the figures above, you can see just how well the intelligence behind our cache can scale even when it faces such a steep workload.

Below you will find a breakdown of each test:

512 MB cache:

Breaking down into the figures, on the 512mb cache test, it’s clear to see just how well ThinIO deals with the tiniest of caches:

When we side by side this with our baseline averages, you can see we take a huge chunk out of that Spiky login pattern and continue to  reduce the steady state IO as the test continues:

So lets move up and see how we get on!

1024 mb cache:

Doubling up our cache size we see a great increase in both read and write savings as you’d expect.

With 100mb of cache per user, and the average user profile in the test 3 times that size. We are still under pressure. As we will natively favour optimisations to write IO over read, you’ll see the bulk of improvements happen in write when we’re under pressure as illustrated in this test:

With more cache available during the peak IO point, we make further savings on write:

2048 mb cache:

and at our recommended value of 200mb per user in Remote Desktop Services, the results are phenomenal! With this size, even still below the 300mb mark per user profile, the read IO gets a really good boost and the write IO saving well over the 95% mark!

And the side by side comparison is every bit as good as the savings illustrated above, reducing that peak bursty IO to just 41 IOPS:

But there’s more! 

As i pointed out in the previous blog, IOPS are just one side of the story. A reduction of data throughput to the disk is also a big benefit when it comes to storage optimisation, and as you can see we make a big difference:

Wrap up:

So there you have it, with ThinIO, a simple, in VM solution, you can you seriously reduce your IO footprint, boost user performance and achieve greater storage density per virtual machine or on Remote Desktop Services technology.

In the mean time:

If you would like a chance to test ThinIO pre-release, find access to the public beta below. Thank you for your time and happy testing!

• ThinIO facts and figures, Part 1: VDI and Ram caching.

Getting right to it:

In this industry when somebody says ‘boot storms!’ – most of us will respond with:

Boot storms are a well documented, boring problem and have many solutions available from vendors and hypervisors alike. Most solutions today rely on a ‘shared memory’ storage area to cache ‘on boot’, in theory caching only one startup or one pattern in order to then serve it back to the proceeding desktops to boot.

But why are boot storms an issue? While working on ThinIO we had the unique ability to really dive into the Windows boot process and analyse why boot storms cause the damage they do and in this post we thought we’d share our findings to better document the issue.

Boot data:

Taking a typical windows 7 boot, to the login screen and idling until all services have started, the data traversing from disk to VM is relatively small. in our testing we found an average of Just 500-600 mb of data is read during this process, and write data barely registers at between 20 and 30mb.

But hey, what gives? Taking such low data throughput, why is boot such a contenscious issue? Have I been misled with marketing and vendor nonsense?

The IO chestnut:

Sadly no, it’s the way windows requests this data, but don’t take my word for it…. Behold, the incredible mess that is the Windows boot process!

Yep, that’s right, in the time Windows requested roughly 600mb of data, it sent down an astounding 70 thousand IO’s in the space of 2-3 minutes!

Math time:

Now if you were to take these figures as they stand, you would take 70,000 IO’s divide this into 560mb and you’d probably end up with an average of about 8k of data requested per IO… You’d be wrong.

As my good buddy Conor Scolard would say, ‘when you Assume, you make an ass out of you and me’.

To better understand the bounderies of Windows, Windows requests IO’s between the minimum of 512 bytes all the way up the spectrum later in the boot process to 128k and above. But it requests these blocks sparcely, on demand, and not just once per sector, the same blocks are frequently accessed.

The net result of this causes absolute havok on the storage:

The crux of the issue is, for each one of these IO’s, the storage provider needs to compute the block data requested, seek the data out, then return it.

But 70,000 of these IO operations for a meagre 600mb of data is madness and you can now see exactly why boot storms were labelled as such for those early adopters who had their hands burned by this fact finding mission.

I’ll mitigate this issue by just booting my VM’s at night!

I’m sure you will! I would also love to see your face if a number of users happen to restart their desktops during the day, cascading 70,000 IO’s per desktop to the storage in a 2 minute window, per desktop!

Bootstorming IS an issue.

Now, knowing all this, it makes sense as to why storage and hypervisors alike are using a cache of ram.

But how does ThinIO fit in here? With Read Ahead of course!

Knowing the Windows boot process as intimate as only a technology like ThinIO can, there are many, many optimisations we can make to this process.

We can both speed the boot process up and also massively reduce the storage requirement while in VM, without any fancy caching mechanism!

With ThinIO’s read ahead technology, we can deliver just shy of an 80% boot IO reduction with nothing other than having our technology in the virtual machine:

Taking a ThinIO averaged test and overlaying it to a baseline averaged test, it’s clear just how much impact this technology can have:

Wrap up:

So there you have it, with ThinIO, a simple, in VM solution, not only can you seriously reduce your IO footprint, boost user performance and achieve greater storage density per virtual machine, you also can also massively negate the impact a booting VM has on your storage.

If you would like a chance to test ThinIO pre-release, find access to the public beta below. Thank you for your time and happy testing!

Test, test, review and tune. Rinse and repeat!

We’ve spent months load testing, tuning, fixing and retesting ThinIO. And for the first time we’re going to start talking about the dramatic results ThinIO can have on storage scalability and user perceived performance.

During our extensive testing cycles, we’ve covered:

• Horizon View
• Citrix XenDesktop
• Microsoft RDS

We’ve been seeing very similar, if not identical results when testing against pools on the following storage types too:

• XenServer SR
• VMFS
• NFS
• Microsoft Clustered Shared Volumes

For reference the statistics we’re sharing today are based on VDI via VMware Horizon View 6, these figures are averages across at least three independent tests. All details of the tests that exported these results are covered below.

Testing details:

The VM’s we tested in this particular workload are as follows:

• Testing Method: Login VSI 4.1 Medium Workload
• Operating System: Windows 7 x64 SP1
• System ram: 3gb
• vCPU: 2
• ThinIO cache: 350mb
• Technology:  VMware Horizon View 6
• Test runtime: 1 hour*
• Statistic sample period: 5 seconds.

With that out of the way, lets jump right in!

Storage IO:

The number of IO’s per second is crucially important when dealing with storage; many, many small IO’s sent to sparse locations on disk are a killer to storage technologies, only made worse by certain file systems.

As a storage acceleration and negation technology, were extremely happy with the IO’s reduction we see on the storage:

Even with just 350 MB of ram as a cache, we achieve phenomenal IO reduction.

Storage MB / Sec:

But IO’s are just one part of the puzzle, what about the size of the data requests being sent to the storage?

A true solution to take the pressure off the SAN, improve user performance, and increase storage density needs to tackle both the IO and the throughput problem.

As you can see above, with just 350mb we’re very good at it!

Side by Side Comparison:

So rounded figures are fine so long as the data is trustworthy, but here’s a real preview laid bare for your analysis.

Here’s a direct comparison on NFS and VMFS of taking a standard load test IO pattern and comparing it to an identical test with ThinIO installed in the VM:

VMFS:

NFS:

As you can imagine, we’re extremely proud of what we can achieve with as little as 350mb per desktop.

The beauty of our approach is simplicity, your users can see this benefit not in a matter of weeks, days or even hours. ThinIO can be up and running in minutes, delivering reduced login times, storage acceleration and providing a far deeper density on your current storage.

Wrap up:

So there you have it, we’ll be adding additional blog posts in the coming days looking at Remote Desktop Services / XenApp, intelligent cache management built in and our Read Ahead technology, so check back. In the mean time, if you would like a chance to test ThinIO pre-release, find access to the public beta below. Thank you for your time and happy testing!

* Eight-hour figures and complete statistics are also available, we have nothing to hide and we’d encourage you to get in touch with the ThinScale team and we’ll share them with you.

For those unfortunate enough to miss synergy or our Webinar with Erik over at XenAppBlog, here’s a little blog post you will find interesting as I walk you through the inners of ThinIO and why it’s so simple to deliver disk access with RAM speeds without any of the complexity.

What is ThinIO?

ThinIO is a filter driver which operates at a block level, inline between the windows and the disk.

ThinIO sits in the operating system layer and can be used on windows desktop operating systems or server based computing models.

ThinIO delivers a greatly reduced IO footprint on your storage, while also speeding up core items like boot times and login times. ThinIO also helps standardize the peaks your storage will get hit by at busy periods during the day. Ultimately this allows you to size your storage for an average, as opposed to sizing for the worst case scenario during peaks.

How does it work?

When ThinIO starts up, it allocates a configurable cache of reserved RAM to perform its optimisations.

Being the last filter in the stack, ThinIO can still allow windows to perform it’s own optimisation on IO, delivering value by catching the read and write IO’s just as they hit the disk.

ThinIO interacts with block data as read’s and writes traverse the cache. As a read is observed it is retrieved from disk and subsequently stored for future use, meaning any subsequent read will be served directly from cache.

But read’s a boring, and everyone has a solution for read caching. ThinIO also treats this RAM cache as a storage area for write IO. Write IO is committed nearly instantly to the cache and no IO is sent down to the disk while free space is available in the cache.

“But what about if the machines run out of RAM?”

Well I’m glad you asked! The cache in ThinIO is hard set at a value you configure, so RAM will never be taken from the cache to service other processes. But in the situation where the cache has become 100% volatile write, ThinIO will then begin to spill over to the local disk allowing the Virtual Machine continue to operate.

There’s more, ThinIO actively manages cache contents to ensure it’s as relevant as possible. As the cache begins to fill, ThinIO’s Lazy Page Writer can identify and flush out blocks that have not been frequently used. This allows you to use a relatively small cache size while still deliver the big numbers we’ll discuss later.

Designed to be fool proof:

ThinIO’s GUI is fool proof, it’s intuitive and gives you a really quick view of ThinIO Realtime. ThinIO provides graphical representations of stats on reads, writes and cache usage, as well as an immediate view of the benefit ThinIO has created for the desktop.

The ThinIO console can also remotely connect to machines to ensure you don’t have to disturb the user while checking performance.

When the cache is enabled, ThinIO also has a realtime statistics window to help you identify disk patterns and cache performance

Boot and application launch time optimization:

ThinIO has some really clever technology built in to optimise the windows boot process and user experience.

During early testing, we observed just how inefficiently windows uses its disk resources during the boot process. Regularly the same files are requested over and over again on boot, if these blocks are non-contiguous, seek times are inherent. Busy servers were requesting up to 80,000 read IOPS during boot and process start.

ThinIO’s Read Ahead feature allows you to teach windows to be less of a storage monster. As the ThinIO cache is already aware of all blocks needed to boot, or even serve the users first launch of their applications, Read Ahead allows you to boot the machine, with a preloaded cache of required blocks, sorted contiguously.

When ThinIO starts up, it identifies the ‘Read Ahead’ configuration file and pauses windows while it reads the required blocks once, in a contiguous pattern around the disk. Once finished, windows continues to boot retrieving the majority of its block data directly from cache.

By doing this, ThinIO was delivering roughly 30% improved boot times while also reducing boot IOPS by over 80% in our testing. In the below graphs, we did a side by side comparison of the windows start-up process with and without ThinIO.

In the Gui below you will see a machine with the ThinIO cache enabled but no read ahead configured, we achieve a good 40% reduction of IOPS on boot and login, which is not bad on it’s own, but we knew we could make it better:

So after configuring a ‘Read Ahead’ configuration by booting a machine, logging in, opening the core set of applications and committing the file we see the following, large improvement of IOPS saving and cache hit rate on read:

So there you have it. By taking an additional 3-4 minutes with your golden image, you reduce nearly 30,000 IOPS to roughly 5,000 IOPS while also reducing boot times. Not only have you taken alot of pressure off your storage, if you launched your users applications core files as part of the read ahead configuration, your user’s login speeds will receive a really good boost while making their application launch times near instant.

Once the read ahead is complete, the driver will then start to use the data which is no longer needed for more chatty blocks of read or write, so configuring read ahead has zero impact on cache usage in the longer term.

Deploy, size, done.

Out of box, ThinIO takes less than 5 minutes to install and configure delivering you immediate benefits. No hoping, trusting or praying the hardware vendor’s figures are correct. No SAN or LUN type requirement, no hardware lead time, no hypervisor requirements and no change needed to your architecture. Whether you are doing on premises or even cloud SaaS / DaaS, ThinIO installs without any change.

Licensing:

ThinIO will ship with a 30 day grace period for you to test to your heart’s content without any commitment. If ThinIO is not for you, it’s just a matter of uninstalling it! Keeping in the spirit of the community, ThinIO will even have a free version available!

Ultimately, designing and deploying virtual desktops is difficult, we really wanted to write a product that both delivers and is simple and easy to deploy. We feel we’ve absolutely hit the mark on this and we look forward to opening the program to full deployment in the coming weeks.

Sounds great, how do I learn more?

Head on over to the ThinScale Technology web page and read more or register for the private beta.