06-30-2010 01:11 AM
Hello all,
I am having a big performance issue when restoring using GRT from tape. I have an open case with Symantec, but so far no cream.
Basically, I have a 256Gb VMDK.
If I restore the VMDK to the local BE media server's E:\ drive (using VMware redirection), it restores the whole VMDK in less than 2 hours at an average speed of more than 2.2Gb / min.
However, if I restore a small file from inside that same VMDK using GRT (using the same E:\ drive as staging location), it takes 8 hours to finish! As I check the speed, it begins staging the VMDK at 3Gb/min, but this logarithmically decreases to 200Mb/s near the end.
There's clearly a problem with BE here. The same VMDK restored to the same local drive has completely different performance depending on whether we are doing a VMDK restore or a GRT restore!
have attached an excel file comparing speed graphs for VMDK restore and GRT restore jobs for 256Gb and 100Gb VMDKs, both of them showing the issue (I used a "timed screenshot" program to capture status every 15 minutes).
Any help would be appreciated, since Symantec support has not even been able to reproduce the issue at their labs even after three months of exchanges.
Regards,
Gaston
---------- UPDATE 2011/03/19: Problem solved! -------------
After more than 6 months of exchanges, finally Symantec has found a solution for this problem. First, I upgraded to BE2010 R2 SP1, which reduced GRT restore time in the above case from 8h to 3h30m. Then, they recommended me to apply the below registry keys:
1. Go to "HKEY_LOCAL_MACHINE\SOFTWARE\
2. Create a DWORD “Enable Buffered Writes" and set to “1” (decimal)
3. Create a DWORD "Number of Write Buffers" and set to “4” (decimal)
4. Create a DWORD “Size of Write Buffers" and set to “512" (decimal)
The above registry keys took download time down to 1h45 minutes, pretty much the same time it takes to restore the VMDK to the local E: drive of the media server.
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