Backup speed from tape to tape in IBM 3584

[ico]

Dear Readers,



Have you any experiences with the subject?

I use TSM 5.1 on win2k server and use FC drives in the library, I backup mostly fileservers, and I can measure about 35 GB/h wich is rather week as I think, because theoretical speed of the drives is about 100 GB/h. What do you think, where is the bottleneck?



Thanks,

Ico

 

[AndyRH]

One of the reasons we used AIX servers for TSM is because most Intel servers can not handle the high data rates of very many FC drives. To take advantage of the tape drive speed you have to not overload the fibre and PCI busses. In my world of 3590E (14Mbs native) drives, I can only run about 6 drives on a fibre to avoid overloading the 2gig fibre. With 15 drives I have to have 3 FC controllers. At this load one 2gig FC controller will fully utilize one 64bit PCI bus. When you add in the FC disk controllers for disks and two 1gig Ethernet cards I need 7 PCI busses to prevent contention. I have not found a suitable Intel server yet. Since you are running LTO, you will have fewer drives per FC controller.

I would suggest that you add up the bandwidth required for each FC controller, do not forget tape drive compression, then determine if you are overloading the FC controller or the PCI bus. I would suspect the PCI bus is the problem.



I hope this helps.



Andy