Urgent Help with VMDK File issues (Block size)

[samuk]

Hi,

We have an issue with our Exchange server.

The D drive resides on a Datastore with a 2MB block size.

Last week the D drive of the Exchange server was extended from 400GB to a maximum size of 512GB. Disk part used to then extedn the volume in Windows.

Veeam backups are failing as the snapshot can not be created on the 2MB block size Datastore.

I have found this: and it seems the overhead was over looked?

http://www.veeam.com/kb_articles.html/KB1091/Backup_Replication:1/file%20is%20larger

Two options i can see are:

1: You may want to move the machine to storage with a bigger block size.

2: You may want to edit the VMX file, so that snapshots will be created on a different datastore that has a bigger block size. Refer to the knowledge base link below for further details:

Any recommended way for me to move forward on this..?

I was thinking option 1, however un sure if i will be able to move the VMDK as snapshot files already exisit on the datastore..

Thanks in advance.

[jamesbowling]

I would commit the snapshots and move the VMDK to a larger datastore.

[samuk]

Hi,

thanks, was not sure if i can commit the snapshots..? is this 100% safe todo with the curent disk layout (512GB on 2MB Block Size)

also we not had a backup of this server for near 4 days, and am little worrres about some thign failing during the migration process?

[jamesbowling]

I would check with VMware Support but I am pretty sure you should be able to commit the snapshots as your VMDK will not be going over 512GB.  That is if I am understanding your issue.

[samuk]

what is the largest vmdk file size for datastore with a block size of 2MB?

Is it 512GB - 512 Bytes?

Thanks

[jamesbowling]

Check out this KB Article:  http://kb.vmware.com/kb/1003565

That article lists all of the maximums for VMFS.

[a_p_]

... however un sure if i will be able to move the VMDK as snapshot files already exisit on the datastore

I'm a little bit confused. How could there be snapshots for this virtual disk!? Can you please explain this and/or post a screen shot of the datastore browser window showing the vmdk files and their sizes, time stamps, ...

André

[a_p_]

what is the largest vmdk file size for datastore with a block size of 2MB?

Is it 512GB - 512 Bytes?

Depends on the ESXi version. For 4.0 it's 512GB-512B, for 4.1 it's 512GB. However if you need to be able to take snapshots, the table at the bottom of http://kb.vmware.com/kb/1012384 (Calculating the overhead required by snapshot files) is what is important.

André

[samuk]

Action Plan:

• NT Backup is in progress of the Exchange Server
• All VM's migrated from another Datastore to a SATA store
• The Datastore deleted and re-created with a 4MB block size
• The Exchange VM will be powered off,
• Create a snapshot  (as advied by VMware support)
• delete all snapshots
• Power up server to ensure it still works ok
• Shut Down server
• Migrate the D drive will be migrated to the new Datastore with the 4MB block size.
• Power up server

Any thoughts?

Hi Screen shot attached

[a_p_]

Does not sound bad. Maybe some thoughts.

1. I'm not sure if create/delete all for the snapshots will delete the .vmsn files!? To me it looks like these files are orphaned files, due to the issue with not being able to create the snapshot .vmdk files. You may want to take a look at the VM's HDDs settings to see whether or not they point to the base .vmdk file. In addition to this, take a look at the Snapshot Manager. Does it show any snapshots? (Maybe you can attach the .vmx and .vmsd file to see how they look like)
2. Migrating the 512GB virtual disk to a datastore with a 4MB block size will not help if the VM's base files are still located on a datastore with a smaller block size. ESXi4 creates the snapshots in the VM's base folder by default. So you either need to migrate the whole VM to the new datastore or set the workingDir in the VM's configuration file (.vmx) to redirect the snapshot. With ESXi5 this behavior changed and snapshots will be created in their parent's datastore by default.

André

[samuk]

Hi,

I have checked the disks from the properties of the VM - and the disk names are corect:

• Hard Disk 1 - Exchange01/Exchange01.vmdk
• Hard Drisk 2 - Exchange01/Exchange01_1.vmdk
• Hard Diskl 3 - Exchange01/Exchange01_3.vmdk

Snapshot Manager does not have any snap shots listed under it.

The VMX and VMSD Files are attached - can you please let me know asap as i am due to carry out this work in a few hours. (6)  (thanks for the help)

Also noted to move the entire VM rather then just the 512GB VMDK File.

If the files are orphansed, can i leave them and just migrate?

[a_p_]

As far as I can see, everything is ok with the two files and the .vmsn files are most likely orphaned. Anyway, since you are going to migrate the VM to the other datastore, any unneeded files usually remain in the old datastore and can be deleted once the VM is up and running from the 4MB datastore.

If you are unsure, post a list of the remaining files once the VM has been moved and/or rename the VM's folder on the "old" datastore prior to deleting the files. This way you would be able to restore them if needed (what I don't expect).

André

[samuk]

so no need to create a snapshot and commit? or shall i do this anyway?

[a_p_]

It does not hurt to if you do this. However, since there are no snapshots on the VM it does not make much sense in my opinion.

André