Highlighted
RRR
5 Tungsten

Formatting a disk in Hyper-V is slow

Jump to solution

I have a 9TB LUN which I attached to a Hyper-V host and I want to format this LUN to become a CSV (cluster shared volume), but the formatting takes hours. The LUN resides on a Dell EMC Unity 450F (all flash). Does anyone know how to speed things up a bit?

Labels (1)
0 Kudos
1 Solution

Accepted Solutions
Mich6
2 Bronze

Re: Formatting a disk in Hyper-V is slow

Jump to solution

Thanks for the extra information.

Slow format's can be caused by TRIM/UNmap being enabled by default on Windows 2012 and above. Although you don't mention the OS version you are running.

The issue arises when a format starts on the LUN, trim identifies space to reclaim and begins attempting to unmap/trim the allocated tracks. This can also cause performance issues to the array by flooding it with unmap commands.

To disable use the command: fsutil behaviour set DisableDeleteNotify 1

Regards, Michel.

11 Replies
Mich6
2 Bronze

Re: Formatting a disk in Hyper-V is slow

Jump to solution

https://blogs.msdn.microsoft.com/clustering/2012/04/06/how-to-add-storage-to-clustered-shared-volume...        

Shouldn't you be doing just a "Quick Format" of NTFS on the volume first and then add it as a CSV into cluster?

Regards, Michel.

0 Kudos
RRR
5 Tungsten

Re: Formatting a disk in Hyper-V is slow

Jump to solution

Yup, that's what I'm doing. But even a quick format is slooooow. And I'm seeing it on LUNs presented by VNX, Unity, Unity AFA, XtremIO. Quick Formatting (in diskpart) is always slow. It is slightly faster on all flash arrays, but it's still slow. On average it takes up to 15 minutes for a 2TB LUN, but like in my question, the 9TB LUN took much longer.

0 Kudos
Mich6
2 Bronze

Re: Formatting a disk in Hyper-V is slow

Jump to solution

That does not sound right. Recommend opening a service request. Run the test, collect an EMCReports and attach to the service request.

Regards, Michel.

0 Kudos
RRR
5 Tungsten

Re: Formatting a disk in Hyper-V is slow

Jump to solution

I know disabling VAAI on VMware is (or was?) a best practice to speed things up, but there must be another way, right? I will open an SR to have Dell EMC produce a valid answer, but I'd appreciate it if forum peeps have solutions as well 🙂

0 Kudos
Mich6
2 Bronze

Re: Formatting a disk in Hyper-V is slow

Jump to solution

Normally for simple issues yes... but my guess is that there maybe a connection issue, and an EMCReports with the HBAinfo.txt file collected may indicate an issue down 1 x HBA.

0 Kudos
RRR
5 Tungsten

Re: Formatting a disk in Hyper-V is slow

Jump to solution

every Hyper-V host has the same "problem" and we have dozens of them in various clusters, spread over various data centers, connected to a variety of storage systems (VNX2, Unity, Unity AFA, VMAX, XtremIO, you name it). It simply cannot be a defective HBA or drivers since we have quite a variety of them.

0 Kudos
Mich6
2 Bronze

Re: Formatting a disk in Hyper-V is slow

Jump to solution

Thanks for the extra information.

Slow format's can be caused by TRIM/UNmap being enabled by default on Windows 2012 and above. Although you don't mention the OS version you are running.

The issue arises when a format starts on the LUN, trim identifies space to reclaim and begins attempting to unmap/trim the allocated tracks. This can also cause performance issues to the array by flooding it with unmap commands.

To disable use the command: fsutil behaviour set DisableDeleteNotify 1

Regards, Michel.

RRR
5 Tungsten

Re: Formatting a disk in Hyper-V is slow

Jump to solution

thank you, that was what I was looking for!

0 Kudos
dynamox
6 Gallium

Re: Formatting a disk in Hyper-V is slow

Jump to solution

Did it help the issue RRR ?

0 Kudos