It's not an official pronouncement, but the Using IBM LTO Ultrium with Open
Systems redbook SG24-6502 has this statement on page 24:
Restriction: At this time, sharing a HBA with Disk and Tape is NOT
recommended. In many instances, the microcode or device drivers HBAs
required to support the different devices makes this impossible in any
case. In
addition, disk and tape usually generate very different types of I/O
accesses,
and using the same HBA will likely give poor performance. You should check
with your local support organization for details of specific recommended
and
supported combinations.
_____________________________
William Mansfield
Senior Consultant
Solution Technology, Inc
630 718 4238
Allen Barth
<allen_barth@SCUD To: [EMAIL PROTECTED]
DER.COM> cc:
Sent by: "ADSM: Subject: Re: Bad performance with FC
attached disk and tape
Dist Stor
Manager"
<[EMAIL PROTECTED]
.EDU>
02/21/2002 03:58
PM
Please respond to
"ADSM: Dist Stor
Manager"
Joshua,
I've heard this before, but I couldn't find anyone at IBM to confirm it.
SO.........
I've been running tape and dasd thru the same FC adapter for about a year
now. Traffic goes from rs6k to an IBM2109 (brocade) switch and then splits
from there. I suspect the switch is handling the arbirated loop (3590) and
point to point (ess aka shark) communication conversions.
Gotchas?
Al Barth
Zurich Scudder Investments
"Joshua S.
Bassi" To: [EMAIL PROTECTED]
<[EMAIL PROTECTED] cc:
OM> Subject: Re: Bad performance
with FC attached disk and tape
Sent by:
"ADSM: Dist
Stor Manager"
<[EMAIL PROTECTED]
IST.EDU>
02/21/02 12:56
PM
Please respond
to "ADSM: Dist
Stor Manager"
Not only is sending disk and tape data across the same FC card a bad
idea, I believe IBM doesn't even support that configuration.
--
Joshua S. Bassi
Sr. Solutions Architect @ rs-unix.com
IBM Certified - AIX/HACMP, SAN, Shark
Tivoli Certified Consultant- ADSM/TSM
Cell (415) 215-0326
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]] On Behalf Of
Wu, Jie
Sent: Thursday, February 21, 2002 8:31 AM
To: [EMAIL PROTECTED]
Subject: Re: Bad performance with FC attached disk and tape
>From the info you provided, your primary stgpool, the diskpool on
Compaq
disk cabinet, and the migrationpool defined on the 3584-L32 are sharing
the
same FC card. If thishis is the case, it is a bad design. You may use
two FC
card on the P610. One for the Compaq FC disk cabinet and the other for
the
3584-L32. I believe this way you will get better performance.
Jie
-----Original Message-----
From: Daniel Sparrman [mailto:[EMAIL PROTECTED]]
Sent: Thursday, February 21, 2002 1:22 AM
To: [EMAIL PROTECTED]
Subject: Bad performance with FC attached disk and tape
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
-----------------------------------
Daniel Sparrman
Exist i Stockholm AB
Bergkällavägen 31D
192 79 SOLLENTUNA
Växel: 08 - 754 98 00
Mobil: 070 - 399 27 51
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