Some technlogies you just need to see in action instead of reading about it. I have posted a video on Vimeo that shows ODX in action on Windows Server 2012 R2 and a DELL Compellent SAN running Storage Center 6.3.10 firmware that supports UNMAP & ODX. Watch the video here or on Vimeo itself for a better experience. It’s a rerun of the demo scripts used in my TechNet Belux Live Meeting of this week.
We demonstrate the amazing speeds at which we can create VHDX files on both a traditional clustered disk and a Cluster Shared Volume. If you have ever tried to create a lot of fixed VHD/VHDX files, especially larger one, then you really need to check out ODX and its potential. If you have a SAN or think about acquiring one make sure you get this feature and be sure that it works as advertised.
I hope you enjoy it and inspires you to look where you can leverage this technology in your own environments.
Recently we’ve been trouble shooting some weird SQL Server to file backup issues. They started failing on the clock at 06:00 AM. We checked the NICs, the switches, the drivers, the LUNs, HBAs, … but it was all well. We considered over stressed buffers as the root cause or spanning tree issues but the clock steadiness of it all was weird. We tried playing with some time out parameters but with little to no avail. Until the moment it hit me, the file deletions that clean up the old backups!We had UNMAP enabled recently on the SAN.
Take a look at the screenshot below an note the deletion times underlined in red. That’s with UNMAP enabled. Above is with UNMAP disabled. The Backup jobs failed waiting for the deletion process.
This is a no issues if your backup target is running something prior to Windows Server 2012. if not, UNMAP is disabled by default. I know about the potential performance impact of UNMAP when deleting or more larger files due to the space reclamation kicking in. This is described here Plan and Deploy Thin Provisioning under the heading “Consider space reclamation and potential performance impact”. But as I’m quite used to talking about many, many terabytes of data I kind of forget to think of 500 to 600GB of files as “big” . But it seemed to a suspect so we tested certain scenarios and bingo!
Disable the file-delete notification that triggers real-time space reclamation. Find the following value HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlFileSystemDisableDeleteNotification and set it to 1.
Note that: This setting is host wide, so for all LUNs. Perhaps that server has many other roles or needs to server that could benefit from UNMAP. If not this is not an issue. It is however very efficient in avoiding issues. You can still use the Defragment and Optimize Drives tool to perform space reclamation on-demand or on a scheduled basis.
Create LUNs that will have high deltas in a short time frame as fully provisioned LUNs (aka thick LUNs). As you do this per LUN and not on the host it allows for more fine grained actions than disabling UNMAP. It makes no sense to have UNMAP do it’s work to reclaim the free space that deleting data created when you’ll just be filling up that space again in the next 24 hours in an endless cycle. Backup targets are a perfect example of this. This avoid the entire UNMAP cycle and you won’t mind as it doesn’t make much sense and fixes you issue. The drawback is you can’t do this for an existing volumes. So it has some overhead & downtime involved depending on the SAN solution you use. It also means that you have to convince you storage admins to give you fully provisioned LUNs, which might or might not be easy depending on how things are organized.
UNMAP has many benefits both in the physical and virtual layer. As with all technologies you have to understand its capabilities, requirements, benefits and draw backs. Without this you might run into trouble.
So you have been playing with or down right seriously testing Windows Server 2012 and perhaps even Windows Server 2012 R2. That’s great. Many of you might have it running in production or are working on that. That’s even better.
Windows Server 2012 has brought us unseen capabilities & performance enhancements that make it a future proof fundament for many versions to come and it is ready for the ever accelerating pace of hardware improvements. R2 has fine tuned some points and added improvements that are stepping stones to better today and even greater in vNext. I’d like to invite you to a free TechNet Live Meeting on Hyper-V Storage Efficiencies & Optimizations in Windows Server 2012 R2 and look at some of these capabilities with me.
As a virtualization guy two subjects are very dear to me and that is networking & storage, and this event is about a subset of the storage improvements. You might have heard about ODX and UNMAP but you have not had the change to play with it. You have read about the tremendous scalability of the IOPS in a VM and about large sector support for the next generation of hard disks drives. Well some of these we’ll demonstrate (ODX, UNMAP, Dynamically expanding VHDX performance) if the demo gods are with us. Others we’ll discuss so you’ll know where this comes into play and how you’ll benefit from them even without realizing you do. So without further delay register for the free TechNet Live Event here.
The Windows 8.1 (Pro) and Windows Server 2012 R2 RTM builds are available right now to the IT Pro & Developers communities via MSDN and TechNet subscriptions. Windows 8.1 RTM Enterprise edition will be available later this month.
Microsoft has decided to get the bits into our hands earlier due to our feedback that we need them to prepare for roll outs & test applications. This is great news and I’m happy Microsoft acted on the feedback they got from us.
So I’m already downloading …
So it seems the next weeks will get even busier than we had bargained for. Happy testing and remember, we weren’t born to follow