Even though there may be a slight performance hit on writes, I've placed
the TSM DB on RAID-5 to ensure availability and no down time in case of
a disk loss.

>>> raghu AT COSMOS.DCMDS.CO DOT IN 10/22/02 08:03AM >>>
Hi,

There was a lot of discussion on this topic before.But i am requesting
TSM
gurus give their comments again.

The set up is like this.

TSM Server : Windows NT 4.0 SP6, TSM 5.1.0.0

                            392 MB memory, P III

                  Adaptech Ultra SCSI

                Hard Disk :  Internal   Hardware RAID 5:

                         array A : 8.678GB * 3 : 17.356GB data and
8.678 GB
parity

                         array B : 35.003 GB * 3 : 70.006GB data and
35.003
GB parity.


Both array A and array B are connected to the same channel.

OS and TSM 5.1 are installed on array A

TSM data base, recovery log and Disk storage pool are installed in
array B.

Database : 2GB+2GB = 4 GB  and mirrored at TSM level on the same array

Recovery Log : 500MB + 500 MB = 1 GB and mirrored at TSM level on the
same
array

Disk Storage pool : 10GB+10GB+10GB+10GB+5GB=45GB on array B


TSM client: 4.1.2.12 ( Tivoli says 4.1.2.12 is not supported with 5.1
Server. But i could take the backup,archive and restore with this
combination )

Number of Clients : 55, all are windows

Incremental backup : 1GB/ client/day.

backup window : 9AM to 6PM with 50% randamization ( all are in polling
mode
)

LAN : 100Mbps

End of the day only 10 clients could finish the backup.Remaining all
are
missing or "?" ( in progress ) or failed.

Through the entire backup window the CPU load is 100% with dsmsvc.exe
holding 98%

I tested with various options. I stopped the schedular and fired 3
clients
backup manually at the same time.Each client has 1 GB of incremental
data.
It took three hours to finish the backup. While backing up i observed
there
was lot of idletime outs of sessions.

Network choke is not there. I checked this with FTP.

Whats the bottleneck here? Is RAID 5 is creating problems ( DB,log and
storage pool all are on the RAID 5 )? I asked the customer to arrange
a
testing machine without any RAID. I will be getting that in two
days.Before
going on to the testing i like to know your comments on this.



Regards

Raghu S Nivas
Consultant - TSM
DCM Data Systems Ltd
New Delhi
India.