speed in backups

[azulita]

Hi,

I running the backups in Legato 7.2.1 in IBM TotalStorage 3584 with 6 drives on a SAN.
The problem is in the speed just run 12Mb/s
when a backup is running it take the 12Mb/s but when start another backup the first change to 11Mb/s and the second backup take 1Mb/s, it happen with all backup clients.
My doubt is: If the drive should be run to 12Mb/s, why all backup clients running to 1Mb/s?

Thanks a lot!

 

[mradamk]

Azulita,

There are many factors which can influence the ability of a tape drive to sustain its rated speed most of which are linked to the ability of the client to read the data from its FS's and package it in preparation for delivering it over the transport mechanism to the tape drive. Things such as local disk speed, IO activity on teh client, CPU activity on the client, number of files involved etc etc etc... Your description is not clear as to whether all tape drives run at 12MB/Sec concurrently, can you elaborate?

1. What model of tape drive is involved?

2. Is the data compressable or has it already been compressed at the client?

3. What type of HBA is being used for the tapes, SCSI or fiber?

4. What is the server type and specs of the Storage node server involved?

5. How does the data reach the Storage node, network? If so, what's the rated speed and are all clients involved using the same network?

6. How many tape drives do you have connected to each HBA?

Regards,

 

[605]

As mradamk states, the conditions for a fast or slow backup process heavily depend on the scenario and are endless.

However, there are some basic tests you may perform which will help you to test what your system is able to achive. In your case i think of the "bigasm" test which may help you to investigate the problem. Please see the NetWorker manual "Performance Tuning Guide" (from the Web) for more details.