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Syncsort Backup Express Speed

Posted by jshah 
Syncsort Backup Express Speed
February 02, 2010 08:30AM
Hello,

We used to use Qualstar 4212 tape drive. We do File level Backup. Simpley going to Backup and then File. We currelty upgraded our backup system to HP StorageWorks MSL4048 which uses LTO Tape Drive.

With Qualstar we used to get about 60GB Per Hour with Two Tape Drive, and with HP we are getting about 150GB per hour with two tape drive. We have a SCSI Card installed on Server which is suppose to give us 320MB per Second, and on HP site they are advertising 1.7 TB/hr for Tape Drive. Obviously we are not getting anywhere close to that. The top backup Speed I have seen is 40 MB/Per Second.

Can anyone tell me if there is any way I can increase my backup speed or that's the way it's going to be?
Syncsort Backup Express Speed
March 07, 2010 01:34AM
[quote]
Can anyone tell me if there is any way I can increase my backup speed or that's the way it's going to be?[/quote]

The first step in troubleshooting this issue is to isolate the bottleneck. The most likely bottlenecks are:

1. Disk Read
2. Network Send/Receive (even on a local backup the data needs to flow from the "Backup Senders" to the "Backup Receivers" known collectively as the "datamovers.")
3. Tape Write.

There are many cases where a higher performance tape drive will actually slow the backup if the data cannot be delivered at a rate allowing it to remain in streaming mode. This forces the drive to repeatedly stop, rewind and then proceed when the data is there. This phenomenon, known as "shoeshining" can cause huge performance problems.

The first thing I would do is mount a couple expendable tapes and run a backup outside of BEX using tar, NTBackup, SBCON, etc. See what your performance is there.

Next, I would look at the Backup Sender and Backup Receiver logs which will give you, among other numbers, statistics on Disk Read, Network Send, Network Receive, and Tape Write.

I Assume you havea dedicated SCSI card for the library and its two drives. Make sure that the two tape devices are on separate buses. The arm (medium changer) can share a bus with one of the drive as it presents virtually no burden to the bus whatsoever.

Too often, support will offer a quick fix by recommending that "Concurrency per Device" be raised in the job definition - In 95% of the cases this is a really bad idea. Although you may win some time by sending multiple data streams to tape concurrently, the costs in terms of Catalog Size, Restore Times, and Data Integrity will almost always outweigh the benefits.

Post your findings here and we will see what we can do. Also post more details of the backup environment (OS, What type of Data, Network or Local backup, etc.).
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