I would say that RAID5 is definitely the problem.  We have seen the same
thing.

Our config is to place the db and log volume on RAID1 (mirror) drives and
the storage pools vols on JBOD disks.

I was astonished by the performance difference.  And this was with hardware
RAID5.

Paul is absolutely correct: for the larger RAID things (ESS, EMC, etc.),
this problem is hidden by the controller.  Probably its cache hardware.

Kelly J. Lipp
STORServer, Inc.
485-B Elkton Drive
Colorado Springs, CO 80907
lipp AT storsol DOT com or kelly.lipp AT storserver DOT com
www.storsol.com or www.storserver.com
(719)531-5926
Fax: (240)539-7175


-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]On Behalf Of
Seay, Paul
Sent: Wednesday, October 23, 2002 4:10 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: RAID5 in TSM


It depends!

Not all RAID-5 is created equal.  NT software RAID-5 is a dog and for that
fact all software RAID-5 solutions are questionable.

IBM ESS under the covers RAID-5 is insulated by the controllers in the ESS,
so you do not care about it.

Paul D. Seay, Jr.
Technical Specialist
Naptheon Inc.
757-688-8180


-----Original Message-----
From: Raghu S [mailto:raghu AT COSMOS.DCMDS.CO DOT IN]
Sent: Wednesday, October 23, 2002 12:31 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: RAID5 in TSM


Paul,


keeping TSM database,log and disk storage pool on RAID5 degrades the
performance???

Regards

Raghu



                    "Seay, Paul"
                    <seay_pd@NAPT        To:     ADSM-L AT VM.MARIST DOT EDU
                    HEON.COM>            cc:
                    Sent by:             Subject:     Re: RAID5 in TSM
                    "ADSM: Dist
                    Stor Manager"
                    <ADSM-L AT VM DOT MA
                    RIST.EDU>


                    10/22/2002
                    06:29 AM
                    Please
                    respond to
                    "ADSM: Dist
                    Stor Manager"





Are you running compression?

Paul D. Seay, Jr.
Technical Specialist
Naptheon Inc.
757-688-8180


-----Original Message-----
From: Raghu S [mailto:raghu AT COSMOS.DCMDS.CO DOT IN]
Sent: Tuesday, October 22, 2002 8:03 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: RAID5 in TSM


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.