VMware & NBU 7.1 - My Experience So Far

[Jorge_F_bregas]

Hello everyone,

I've been playing around with VMware backups & NBU 7.1  and these are the issues I've found so far regarding VM backups:

1. Linux VM backups - Slow

I've been getting around 100 MB/sec to 130 MB/sec of throughput (to our LTO4 tape-drives) with our Windows VMs but I'm only getting around 40 MB/sec to 50 MB/sec for our Linux VMs (all things equal: same datastore, same workload, about same VM size).  I know the ability to perform granular file-restore of Linux VMs is a brand new feature and I'm wondering if the "smarts" to scan & index the ext3 filesystem - within the vmdk - is holding back the backup job?  Is this a known issue? 

I really like the idea of being able to perform individual file restores from our Linux VMs but I just want to know if this is a know issue or if I need to tweak something somewhere.

2. Existing Snapshot Handling

All of our flashbackup-windows polices have the default option of "Remove NBU" on the snapshot section .  That is, at the time of backup, if there's any previous NBU snapshot, Netbackup will delete that snapshot. I just did some tests: 

• created a snapshot of a VM
• performed a full-backup (and while the backup was running I used the vSphere client and checked that indeed there two snapshots:  the one I created previously and the one NBU just created prior to initiating the backup)
• I deleted the VM
• I restored the VM

The end result: my snapshot was gone.  Is this also a known issue? How can I restore my VM and have it with the snapshot (or snapshots) it previously had?

3. Datastore migration & Incrementals

I perform a Full backup on Sunday...then on Monday I shutdown the VM and then move it to another datastore. When the cummulative incremental runs at night it does the backup as if it were a full backup (same size as the previous full).  It seems that the datastore migration confuses NBU or the actual VM blocks change..don't know who's the culprit. I'm not sure if Symantec is aware of this.  I thought I'd let you know that.

4. Restore of VMs with Thin-Provisioned disks

I still have the same problems I had with NBU 7.0 where most of the VMs with thin-provisioned disks will fail on restore.  I'm still wating for a support case I opened with our VAR so I can get the proper EEB for 7.1...

Best regards,

Jorge

[RiaanBadenhorst]

Hi,

Thanks for sharing the information. I would be interested to see what the difference in speed is when you backup both Linux and Windows using Full VM Backup instead of Mapped Full VM backup. You should also be able to see if its the individual file catalog process that is slowing down the linux VM backups.

[Jorge_F_bregas]

Thanks Riaan for the suggestion! That was right on!  I never thought about that.  I jus did it right now with two VMs:  I changed the "Mapped full VM backup" to "Full VM backup" on Policy's options and these were the results:

• Windows VM:  185 MB/sec  (way faster than the usual "Mapped Full VM backup")
• Linux VM:  165 MB/sec  (super way faster than the 40 MB/sec I was getting )

The difference in data-rate I guess is due to high I/O at the time of the Linux backup but the experiment indeed proves that the "x-raying" of the vmdk files (in Linux VMs) is definitely what's holding back the speed of the backups on the "Mapped full VM backups" policies where I was having (constantly) just around 40 MB/sec.  There's a great difference! 

I might consider creating new policies with "Full VM backups" just for those VMs tha we rarely recover individual files.

Again, thanks for the tip!

Regards,

Jorge

[RiaanBadenhorst]

Thanks for posting the result, at least we have some information to work with. I've not really looked at the new feature yet, does the Linux Mapped Full also give you the ability to do INCR, and even better, BLIB?

If it does you should be able to get away with doing those daily.

[Jorge_F_bregas]

I just tried the cummulative incremental (with block-level incremental turned on) and it works indeed.

Regards,

Jorge