Very slow SQL agent performance, but file copying is normal

[mbuyukkarakas]

I have couple of SQL 2005 servers which are running on Vmware Vsphere 4.0. I use BE 2010 to backup them but there is a slow performance problem. 

My findings are ; 

- The SQL job rate never passes 800 MB/min (14 Mbyte / sec)
- If I copy a big sized file from BE to SQL srv, I have a rate like 3.1 Gbyte / min (50 mbyte / sec) or in reverse way.

I cant answer why this is happening. Any idea ?

Thank you.

[CraigV]

Hi there,

Couple of questions:

1. Are you backing up the SQL DBs through the SQL agent, or are you backing up the VMs?
2. What is the speed of your network?
3. What type of device are you backing up too?

Laters!

[mbuyukkarakas]

Hi Craig, thank you for your quick response.

- The network is at gigabit speed.
- The BE server's NIC negotiation is full dup 1000
- Yes, I'm backing up them through SQL agent. I dont back up the VMs.

I investigate a general performance issue in my BE system and as a part of this I stopped all other jobs, I just test the SQL jobs. Thats why I can say that the BE server is just running SQL jobs for a specific duration.

Thank you.

[teiva-boy]

With BE2010, and the AVVI agent, you can backup the VMDK itself, and the agent within the guest will quiesce the Db, commit any transaction logs, and then VMware will snap the VMDK.  But the overall backup duties will be 95% handled by vcenter, the last 5% is for the agent to use VSS and collect any additional meta data.

You will get much higher throughput this way by NOT using an agent to do the backup duties.

[teiva-boy]

Side note, have you looked at any of the performance graphs in vCenter during the backup?  Perhaps you are saturating the physical limits of the box with not enough NIC's, CPU, memory, etc?

[mbuyukkarakas]

Thank you.

Could you be more spesific about the choice between SQL and AVVI agents. I just need to backup the SQL database. In this case why to backup all the vdmk file with too much unneeded things ? Is there such a big perf.difference ?