Backup performace issue

[vjaykv]

Hi Experts

I have recently installed and configured TSM 5.5 server, ISC and Admin Center on an AIX Lpar BOX with an SCSI autoloader (IBM 3310) attached. This box is assigned 2 GB memory with 2 processors. I have also configured and registered an aix client to this server.

We found that the communication between the client and server was successfull.Howerver when initiated a flat file backup from DSMJ console with the primary stgpool as ltopool I am facing a performance problem.

a. The transfer rate is very slow 1.5 mb per Min
b. The server performance also decreases

I have done few tests to over come some assumptions

1. I tried to backup to disk pool as a primary storage pool it completed successfully and i was able to backup 2 GB in 4mins.
2. To cross check with the library i used the AIX commands to write the same contents to the tape it also completed in 4mins
3. The ftp transfer rate between the server and the client was also fine


Please help me how to overcome this situation.....

 

[max]

hi,

what about a migration from disk to tape (disskpool to ltopool) ? Is it as slow as the backup to tape ?

max

 

[umur]

are your storage agent and tape paths configured correctly? what does the output of "validate lanfree" gives?

 

[Cloudrider]

So what does the Client backup output show from 'q act' for network time and aggregate time? Does that give any clues where the hang up is occurring?

 

[n9hmg]

What sort of storage is the flat file on? If, for instance, it's on a single scsi disk, you just can't keep up with a modern tape drive. You have to feed an LTO3 or LTO4 at least 27MB/S or it starts shoeshining. That's a good reason to have almost everything backup to disk, and then let your mighty server feed the tape drives at a speed high enough to be used.

 

[vjaykv]

Hi Guys Thanks for the Update .....

Max : I have to try the migration from Disk To Tape will check that let u Know

Umur: We are not using Storage Agent its a Lan Backup

CloudRider: The Aggr and Network shows bytes transferred during the backup process, the transfer is slow but it dose not varies

N9hmg: The Flat file resides on Local Disk of the server, we are using Ultrium 2 tapes, i will try Migration from disk to tape


I will try with the recommended tips by you guys
thanks ......

 

[BKOOHI]

Check IO performance of your local disk drive. Poor performance of your local SCSI drive might be a contributing factor. If you have SAN disk then move your diskpool to SAN disk and compare results.

 

[n9hmg]

If you backed up 2GB in 4 minutes going disk to disk, that's 17MB/sec, and you're shoeshining that tape. If you go even just a little bit slower than the tapes minimum streaming speed, you'll go a LOT slower. I presume your stgpool disk is fast enough to keep up with the tape. If so, you would be on tape sooner if you backed up to disk and migrated to tape, than going straight to tape.

I once entered a situation where one SCO box without a tape drive rsh'd its data over net to another's QIC drive. It would barely finish in a 12-hour window. After becoming aware of what was going on, I used DD to buffer the stream. On the system with the drive, I used an OBS of 512 to match the drive, and an IBS of 8MB. When I started the backup, my boss said it would never be be done in time, because the tape drive sat silent for 80% of the time instead of constantly going back and forth. 90 minutes later it was done. Also, our use of cleaning tapes dropped precipitously after that.