Anyone been able to reproduce automount issues with VMFS?

[pinkerton]

Hi,

we are in the process of deploying VBR 5 in our vSphere 5 environment want to use Direct SAN backup within our FC SAN. I've read a lot of posts that say when Windows Automount is enabled it could cause Windows to resignature a presented VMFS volume and thus destroy your VMFS partition (though there are ways to recover from this). Before going live I'd like to test such a scenario - enable automount and let Windows issue a signature to a VMFS volume presented to the VBR server. Then see how to recover from it.

However, I've not been able to produce such a situation. Our VBR server is 2008 R2 SP1 and with automount enabled I've tested the following scenarios:

1.
- created a new LUN on SAN, presented it to an ESXi host and created a VMFS datastore
- presented the LUN (while sill being present to ESXi) to the VBR server
- nothing happended! Windows disk manager just shows the partition as online, healthy and labels it as Primary Partiton.

2.
- created a new LUN on SAN, presented it to an ESXi host and created a VMFS datastore
- unmounted the datastore on ESXi and unpresented the LUN from ESXi
- presented the LUN (while now not being present to ESXi) to the VBR server
- nothing happened - just as above!

So, in what scenario does Windows resignature a disk that is presented to it? Anyone knows?

Thanks
Michael

[Gostev]

Hi Michael, don't you get a popup in Disk Management snap-in? I get these every time in my home lab with iSCSI SAN, not sure why you don't get them. It is natural for people not to read message boxes and just click OK assuming that Windows would not suggest bad default choice. Thanks.

[pinkerton]

I think I have only got pop ups with empty disks, but not for ones with VMFS partitions already being present. I also don't have a chance to manually initialize the disk - I know that if you supress the pop up, you still have the ability to right click the disk and choose "initialize". This however is not the case for the VMFS volumes (maybe because they are recognized as Primary Partition).

Did you also test with Windows Server 2008 R2 SP1?

I will do a second test tomorrow, but I think I am quite sure that I didn't get those pop ups for VMFS volumes.

[pinkerton]

I've performed another test with automount being enabled. VMFS partitions show up as Basic disks with "Primary Partition" and I get NO prompt! Empty disks show up as "Unkown, Not Initialized and Unallocated" and I get a prompt to initialize the disk:



You said you even get such a prompt for VMFS partitions. What OS are you using? Maybe its behaviour is different from 2008 R2 SP1.

In general: Will Windows - when automount is enabled - ever *automatically* reinitialize/resignature a disk, or does Windows only show the prompt and the real danger is that someone clicks and reinitializes the disk?

[Gostev]

I am using Windows 7 SP1 but did not have a chance to make some screehshots yet. As far as I know, Windows always prompts, but this may have been different with earlier Windows versions.