VCB and how it's working

[a2pr]

We are trying to get vcp up and running as fast as possible

We are running it with Legato Networker 7.3.3

VCB is installed in a win2003 32 bit (64 bit is not supported.....) with a networker storage node that are doing the the backup to a EMC virtual tape library.

We have this up and running but when we look closer to what is happening we see the following :

When we initiate a vcb backup VC takes a snapshot on the virtual machine - then all the files (vmdk etc) is copied to the windows backup server before the actual backup is performed to the EMC virtual tape library.

That means that you need fast disks on the backup server if you want good performance......and it takes twice as long time to backup a virtual machine....?!?!?

Why is it not possible for vcb to take a snapshot and backup directly to the tape library without temporary copy the files to the backup server???

Is there any configuration we have missed to get this working better??

[zemotard]

Hi, you can do it, but you need to install linux agent on esx (snapshe launched by networker with a pre-command script.then backup on tape)

I have tried this method, and it works fine.

Else with vcb, you can mount the filesysteme and backup it, but not to backup vmdk directly on tape.

Regards

[ianmellor]

Hi,

Are you wanting to do full vm backups?

Here is what happens if you want to do a back ,the system administrator configures backup schedules and policies in the

third‐party backup software.

For example, the system administrator might instruct the backup software to back

up D:\Data on vm37.company.com daily at 3:05 a.m.

2 The backup software schedules this backup job automatically.

3 When the backup software launches this job, it calls into Consolidated Backup by

using a pre‐backup script.

Consolidated Backup performs the following:

a Contacts a VirtualCenter instance or an ESX Server peer, and requests it to

create a snapshot of the virtual machine to be backed up.

b Makes this snapshot available (mounted) on the backup proxy. This makes the

data that needs to be backed up visible to the third‐party backup software.

4 The third‐party backup software performs the backup procedure of copying

changed data to the backup media.

I think maybe your backup software is copying the data to your Proxy Server.

Hope this helps you.

[a2pr]

Hello

What do you mean with :

"Makes this snapshot available (mounted) on the backup proxy. This makes the

data that needs to be backed up visible to the third‐party backup software."

That we see is that the files are copied to to the proxy before it is backed up....is this special because we are usin Legato Networker or...is it by design of VCB?

[ianmellor]

Hi,

What it means is that on your proxy server you see another "hard drive". Like in My Computer you get a F Drive. Then your backup software backs up F Drive, which is in fact mounted from the SAN by VCB.

Hope this explains it?

[a2pr]

Hello

Is it Networker that is doing the "copy" of the files - and other vendors don't??

We can se in some cases when VCB is failing that all files is on the proxy and we have manually deleted/moved these files

[ianmellor]

Hi,

I think it could be. I have not worked with it so i can't say. VCB works by mounting the data on the Proxy Server then your backup Software like Symantec Backup Exec can copy the data. If you are doing a full vm backup then the vm is snapped and copied to your proxy server file level it is not.

Hope this helps.

[dinny]

Hiya,

VCB always copies full VM snapshots to the VCB server first (and mounts file level snapshots on the VCB server)

This is normal behaviour and is the same across all backup vendors.

Dinny

[jeff_james]

That means that you need fast disks on the backup server if you want good performance......and it takes twice as long time to backup a virtual machine....?!?!?

Why is it not possible for vcb to take a snapshot and backup directly to the tape library without temporary copy the files to the backup server???

I believe that the reason for the temporary backup is to enhance performance, for the majority of configurations. There are many factors that would cause a tape library to be less than optimal as the primary location for direct backup.

I am not sure what metrics you have to sustain your contention that "it takes twice as long time to backup". How have you identified the choke point?

In my experience backup to HD prior to backup to Tape is usually far superior in performance to backup directly to tape library.