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dennes
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Slow backup and no changed block tracking

Post by dennes » Dec 22, 2009 9:14 pm

Hi,
I'm backing up an ESXi (licensed) 4 server with 2 VM's. Host is an hp ML350G5. For testing purposes i'm only backing up 1 800GB Windows SBS 2003 VM (hardware version 7).
Veeam Backup (latest version) is installed on an XP Pro Desktop with an attached USB 1TB disk. LAN connection to the desktop is 100Mbit. This Dell pc is a Core2Duo with 3GB RAM.
Problem is that the initial backup takes just about 2 days (avg. 2MB/s) and incrementals do not use changes block tracking, although it is enabled.
The VM has no snapshots.
Network copy of files from lan to the USB disk are about 10MB/s so the lan is not the real bottleneck i guess.

What can cause this increadible slow backup speed and Veeam not using chaned block tracking for the increments?

Thanks,
Dennes

Gostev
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Re: Slow backup en no changed block tracking

Post by Gostev » Dec 22, 2009 9:18 pm

Dennes, what job processing mode are you using, and what storage your test VM is located on?

dennes
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Re: Slow backup and no changed block tracking

Post by dennes » Dec 22, 2009 9:27 pm

Network (with change block tracking and dedup checked in the advanced properties).
The test VM is on a RAID5 array of 4 300GB SAS disks, connected to an HP P410i controller with 256MB BBWC cache. Disk performance inside the VM are ok, so the RAID isn't the problem i guess.

Dennes

Gostev
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Re: Slow backup and no changed block tracking

Post by Gostev » Dec 22, 2009 9:37 pm

Change block tracking is only leveraged in the vStorage API processing modes, try using this one with "Network" option. This should speed up your incrementals.

As for full backup speed, try to shutdown your test VM and copy is disk file to your USB disk drive using VMware Infrastructure Client's datastore browser. If the speed is as low as you are getting during backup, then this would mean that there is an issue with your ESXi host's hardware (storage controller or NIC).

dennes
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Re: Slow backup and no changed block tracking

Post by dennes » Dec 22, 2009 9:40 pm

Ok, i meant i use network on the vStorage API radiobutton, so i'm not using the legacy network option.
I'll check the copy speed from the datastore browser.

Thanks
Dennes

Gostev
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Re: Slow backup and no changed block tracking

Post by Gostev » Dec 22, 2009 9:46 pm

OK, in that case, I would expect changed block tracking to be in use. Or there should be an explanation in the session's log why it is not being leveraged (or why it cannot be enabled).

How do you judge on whether it is being used? Note that you will only see changed block tracking used when the job is copying virtual disk (VMDK) files. When the job processing other small VM configuration files (like VMX), changed block tracking is not used, and you will see "without changed block tracking" status.

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Re: Slow backup and no changed block tracking

Post by dennes » Dec 22, 2009 9:59 pm

Ah.. I was watching the job from the live view and saw the message on the screen (NBD without changed block tracking), but i'm not sure which file it was. I'll have to recheck.

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