Hi

We have a system configured as follows:

One P-Series 610 with dual 450 PowerPC processors
1GB RAM
2 18.2GB Ultra3 15K drives which are mirrored and contains AIX system and
Tivoli logs
2GB Ultra3 15K drives which are mirrored and contains Tivoli database
(30GB large)
One IBM FibreChannel card
One locally attached IBM Magstar 3575-L32 with 3 3570C drives.

The system is attached to a SAN and has a dispool of totally 150GB on a
Compaq FC disk cabinett.

The system also is attached to a IBM 3584-L32 which as 2 SCSI drives
connected through a IBM SAN Data Router (2108-R03) and one fibre attached
LTO drive which is connected through a SAN switch(Compaq).

The system uses 3 100Mbs Ethernet adapters, one which really are a Gigabit
Ethernet card but is running at 100Mbs speed.

When backup occurs, we have a good performance; normally about
15.000-16.000KB/s in Network speed, and about 6000-7000KB/s in Aggregate
Transfer Rate.

However, when the diskpool gets full in the middle of the night, and the
TSM server starts migrating data to the drives in the 3584-L32, performance
drops. We only get about 500KB/s-600KB/s throughput in the fibre attached
drive. The AIX server however, has a good throughput through the FC
adapter, and the Compaq disk cabinett has a throughput of about 10-14MB/s
to the AIX server.

If we do a storagepool backup from the 3575-L32 to the 3584-L32, the speed
is good.

If we do reclamation, or database backup, the speed of the FC drive is also
good.

Can this has something to do with the FC adapter? Should this configuration
require 2 FC adapters?

The first thing that hits me is that the FC adapter can't handle the
throughput, doing both backup from clients to SAN attached disk, and doing
migration from SAN  attached disk to SAN attached drives.

If we do a migration in the morning, when no backups are running, we get a
speed of around 27MB/s on the fibre attached drive with compression. So,
the FC drive has good performance, when no backups are running.

Can somebody tell me whats wrong?

Best Regards

Daniel Sparrman



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Daniel Sparrman
Daniel Sparrman
Exist i Stockholm AB
Bergkällavägen 31D
192 79 SOLLENTUNA
Växel: 08 - 754 98 00
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