Slow performance on FlashBackup Windows restore

[blanco_adalbert]

Hello Everybody!!

I am running backups on a physical server windows client server with a lot of little files on three filesystem drive. The backup is configured as flashbackup because the backup window is restricted and the amount of information is 3TB per filesystem.

The backup is running with multistream. During backup the throughput is 45MB/sec. 

When restoring the throughput is 3MB/s. I have setted up the NUMBER_DATA_BUFFERS, NUMBER_DATA_BUFFERS_RESTORE,  SIZE_DATA_BUFFERS, NET_BUFFER_SZ. There is no performance improvement.

Also the activity monitor does not reflect any change. The bptm log shows io_init: buffer size for read is 262144.

[Marianne]

Are you doing file-level restore or full raw volume restore? What is Client Windows version? If W2003, is TCP Chimney turned off? Have you tried network copy of files outside of NBU? What kind of speed do you see doing network copy?

[blanco_adalbert]

Hello, I am doing a full raw volume restore on a Windows 2008 with a TCP Chimney turned off.

I have to restore three volumes.

2 of them has been restored using file-level restore because of the file characteristics. I mean the files on  those volumes are biger than the files on the third volume.

During the file-level restore the throughput was 30M/s

Thats the reason to restore it using as a raw volume.

[Marianne]

Actually, Symantec only recommends TCP Chimney turned off for W2003 and to be turned on for W2008. I have in the past seen that mismatched NIC and switch settings (auto negotiate vs fixed) caused good backup speed but slow restore speed. Ensure that NBU network buffers on media server and client is set to 0. Something else to look at is LUN layout of the volume being restored to. Poor layout will cause poor write performance.

[sdo]

Hi Blanco, any news on this?

There are always lots and lots of questions re 'backups' on this forum, but not many regarding the purpose of backups - i.e. the ability to be able to restore... and so, questions such as yours are very interesting.  Any news?

[blanco_adalbert]

Hello, 

I am still staged on the problem.

I have faced twice this problem. the first was to backup oracle audit logs on redhat.

I solved this issue running a script on the pre backup policy to create a package of those files before backing up.  Thad improve the backup and restore performance.

On this case the OS is windows and I dont have access to the server in order to run the test. Also the allocated space of the information on the system is enourmus (6TB aprox).