07-19-2011 12:56 PM
A few questions around VMware backups
We are running Netbackup Version 7
I’m just trying to get an exact understanding of this, so please bare with me. A consultancy company configured this setup so it’s all up and running.
We have six ESX hosts - VSphere 4.1 - fibre attached to the storage. These are hosting a number of Windows guest VMs. The Netbackup VMware backup host is attached to same storage
My questions are
Does the VMware backup host draw the backup data directly from the datastore, or does it pull it via an ESX host?
When restoring a VM, unless an ESX host is specified in the alternate restore section, does the restore send the data via the VCenter server and across the network?
Why can’t the VMware backup host restore directly to the datastore and not via the VCenter server or ESX host?
Thanks in advance
JB
07-20-2011 12:20 AM
Hi,
It takes the vmdk's straight from disk and not via the ESX/vCenter (unless you've configured the transport method in the policy to be NBD)
For restores, you can once again choose the trasport type, SAN, NBD, etc.
07-20-2011 12:52 AM
Ok great, thanks Riann.
So if the restore goes directly back to the disk from the Vmware backup host and not via an ESX host, why is there an option to configure an ESX restore host, or am I miss understading this? Our backups are set to go via the SAN.
JB
07-20-2011 01:00 AM
Can you elaborate on this option, are you referring to the recovery host?
07-20-2011 07:33 AM
No.
It's when I tested the restore to an alternate location.
The restore speed is slower if I select the "restore to original location" option. So I’m guessing it’s going via the vCenter server.
It's a lot faster when I select restore to an alternate location then specify an ESX host in the vCenter server field (recovery options dialog).
This section on page 126 of the NBU VMware guide
vCenter Server
Specifies the vCenter server for the restored virtual machine. To use the
Original vCenter Server (the default), verify that the original vCenter server
still exists.
To use a different vCenter Server, make sure that it is compatible with the
virtual machine you want to restore. Note that a vmx-07 virtual machine can
be restored only to a vSphere 4.0 or later server.
The restore may finish faster if you use the SAN transfer type with a restore
ESX server (bypassing any vCenter servers).
I assumed that the VMware backup\recovery host (also a media server) restored the files directly to datastore from which they came. I'm probably just misunderstanding what the manual is trying to say.
07-20-2011 10:19 AM
HI Riaan,
Ok I did a little more testing.
It seems unless we have a "VMware restore ESX Server" configured in NBU admin console "media and device management, credentials, virtual machine servers" then the restore is slow.
Since I've added one of our ESX servers to this section the restore is lightning fast. So the data must be passing through the ESX host and not directly to the datastore like I first thought. Why is this the case?
07-20-2011 11:25 AM
This article kind of answers my question
http://www.symantec.com/business/support/index?page=content&id=TECH127830
But this line is a little confusing
It is not a mounted file system on the Netbackup windows VMware backup host, but it must be "zoned" to be seen with read/write access through the SAN
So is this saying that the Netbackup VMware backup host can't write to this storage directly because it can't mount it? This is why I keep thinking that the data flow goes via the ESX host during backups and restores.
07-21-2011 01:04 AM
Hi
I found this http://www.symantec.com/docs/TECH145126 which could explain it.
07-21-2011 11:50 AM
Make sure you have the latest VMware rollup installed for your version of NBU. You can enable eagerly Scrub, which creates the container before we start writing and elimiates a lot of talking.
07-25-2011 08:05 AM
Thanks Riaan, I appreciate your patience and help with this.
I guess what I’m saying is why is there a need to specify a restore ESX server at all, when the restore data should go directly to the storage attached to the VMware Backup host?
07-26-2011 12:53 AM
Hi,
I'm not really sure as Symantec have not published, and probably wont, how it works on a nuts and bolts level. What you must remember is that Windows cannot mount those disks, as it doesn't understand vmfs. It would then imply that there must still be a level of integration between the windows server (actually netbackup) and the ESX/vCenter as it has to understand where to write on the LUN.
Sorry I cant give you more details but I'm sure its not as simple as just writing to a lun since Microsoft cant read/mount/write to the file system in question.
07-26-2011 04:07 AM
Sorry I cant give you more details but I'm sure its not as simple as just writing to a lun since Microsoft cant read/mount/write to the file system in question.
=> We use our VxMS libs to read from the LUNs. The child job starts bpbkar32.exe, which then depends on the VxMS libs, which are located at c:\program files\common files\veritas\vxms\. If you find in your event viewer vxms warnings, that usually means we had issues our reading a vmdk file. this can happen for multiple reasons. VxMS is the core of flashbackup.
Let me know if you need more information or what information you are looking for.
07-26-2011 06:11 AM
Thanks,
So that confirms there is a lot more going on than just dumping files on a mount (LUN)