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Full Name: Alex

Virtual Appliance config

Post by AlexL »

Any tips/suggestions/specs for the Virtual Appliances? I currently have 5 of them, all W2k3 R2 with 4 vCPU and 1GB. Backup target is a network share.

Is it possible to do SAN mode backup in an Virtual Appliance? All the ESXi 4.1 hosts have shared SAN storage. Unfortionately I do not have multiple physical boxes with hba's. So either I do SAN mode on 1 box, daily backup of around 150 VM's total source size of 5TB or I use multiple appliances using a network share as the target.

In the first option I'm limited by HBA throughput/memory/cpu's. Since backup speed was too slow I switched to appliance mode to increase concurrency but besides that I'm now hitting network limits I still find backup speed slower than expected even when only 1 backup in my complete environment is running.

Any help or suggestions would be appreciated.
Vitaliy S.
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Full Name: Vitaliy Safarov

Re: Virtual Appliance config

Post by Vitaliy S. »

Hello Alex,

The most common recommendation for Virtual Appliance VM is to grant this VM with 4 vCPU (you've already done that, so it's ok) in order to have best performance possible. However, if your VM is still starving on CPU resources (you may check that by opening Task Manager - Performance Tab) during a backup job run, I would suggest using less compression levels for the job. That should give you better performance, though the vbk file will be less compressed.

As regards to SAN mode within a VM, then it is possible to configure only with iSCSI SANs being used. As you already know you cannot virtualize HBA driver, so provided that you have an iSCSI SAN, then Microsoft iSCSI Software Initiator should be used to present LUNs to a backup server.

Actually, both SAN and Virtual Appliance are LAN-free modes, and based on my lab's results there is no much difference in the performance rates for both modes (fulls and incremental passes), though I understand that everything depends on the actual hardware (source/target storage etc.)

Besides, just to compare I would also try using local virtual disks of the Virtual Appliance VM as a destination target to see what the performance will be.

Thank you!
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Re: Virtual Appliance config

Post by Gostev »

I would look at your backup target as well, most likely it is the performance limiting factor with multiple appliances writing to it. Generally NAS is slowest possible backup target (and the fact that data has to go over LAN does not help). People looking for faster backups prefer to backup to NTFS LUN on SAN, or local storage (in case of physical backup servers).

Switching to incremental backup mode with v5 may help to reduce load on NAS and increase speed of incremental runs (because of 3x I/O comparing to reversed incremental mode), however the drawback is much longer backup window on weekend (if that matters).
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