Re: Disk performance issue
From: jeff barratt-mccartney (jbarratt_at_COMPSAT.COM)
Date: 08/19/04
- Previous message: jeff barratt-mccartney: "Re: HACMP 5.1 with EMC SRDF"
- In reply to: Bill Verzal: "Disk performance issue"
- Next in thread: Bill Verzal: "Re: Disk performance issue"
- Reply: Bill Verzal: "Re: Disk performance issue"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Date: Wed, 18 Aug 2004 22:32:02 -0400 To: aix-l@Princeton.EDU
what are you backing up with? 8Mb/sec should never result in 90+ i/o wait.
what does filemon say?
-----Original Message-----
From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU]On Behalf Of
Bill Verzal
Sent: Wednesday, August 18, 2004 1:45 PM
To: aix-l@Princeton.EDU
Subject: Disk performance issue
Hi *,
I am banging my head against a wall on this issue. Hopefully the
collective knowledge can help me with this one.
I have a EMC 3830 SYM. It is maxed out in terms of drives. All drives are
RAID-1 mirrored. Half of the LUNs on the EMC box are Fibre connected (not
via SAN, but point-to-point) and the other half are Timefinder BCV's, SCSI
connected.
When I backup the data to LTO tape (4 tapes needed), by the time I get to
the last tape (or even if I run the 4th tape by itself), the performance of
the backup to tape slows down by an order of magnitude. The previous 3
tapes all run in about 2 hours each, the last tape runs in about 4-hours.
Here is a snapshot of some performance commands:
# symstat -c 3 -i 5
DEVICE IO/sec KB/sec % Hits %Seq Num
WP
08:00:18 READ WRITE READ WRITE RD WRT READ
Tracks
08:00:24 00A2 (rhdisk43) 21 0 2666 0 14 N/A 33
0
00A3 (Not Visible ) 21 0 2677 0 10 N/A 33
0
00A4 (Not Visible ) 20 0 2656 0 5 N/A 25
0
------ ------ ------ ------ --- --- ---
------
Total 473 393 12771 4543 23 100 12
1553
08:00:30 00A2 (rhdisk43) 20 0 2634 0 5 N/A 10
0
00A3 (Not Visible ) 20 0 2709 0 5 N/A 30
0
00A4 (Not Visible ) 21 0 2666 0 10 N/A 24
0
------ ------ ------ ------ --- --- ---
------
Total 560 440 11407 4652 25 100 9
938
# iostat 3 3|grep -v 0.0
tty: tin tout avg-cpu: % user % sys % idle %
iowait
Disks: % tm_act Kbps tps Kb_read Kb_wrtn
hdisk43 94.2 7943.4 63.4 23936 0
hdisk43 94.9 7633.1 60.3 22912 0
hdisk43 96.6 7677.1 61.6 23044 0
So, the EMC box is providing me with about 20 I/O's per second, yet the H80
AIX box is reporting 94% I/O wait.
EMC has been less than helpful on resolving the issue.
Anyone see anything else ?
AIX 5.2, ML-1
H80 6-way, 8GB memory
Thanks, Bill.
--------------------------------------------------------
There are only 10 types of people in the world: Those who understand
binary, and those who don't ...
Bill Verzal
Project Leader, Komatsu America
(847) 970-3726 - direct
(847) 970-4184 - fax
- Previous message: jeff barratt-mccartney: "Re: HACMP 5.1 with EMC SRDF"
- In reply to: Bill Verzal: "Disk performance issue"
- Next in thread: Bill Verzal: "Re: Disk performance issue"
- Reply: Bill Verzal: "Re: Disk performance issue"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Relevant Pages
|
|
