How to determine stripe size and stripe width on HPUX 11.11 for MBRC
Date: Thu, 04 Sep 2008 16:49:18 -0400 (EDT)
Message-Id: <20080904204918.D8E8C5174@arkroyal.cnc.net>
Hello all,
I have inherited several Oracle 9.2.0.8 data warehouses on HP-UX 11.11 servers, each 2+ TBs. All of them are experiencing various performance issues.
The db_multiblock_read_count (MBRC) on these databases are explicitly set to the value of 8. To try to get a better idea of what we might increase the MBRC to, I wanted to figure out the values for the formula:
[stripe width] x [stripe size] / [db_block_size ]
How can I determine the values for stripe width and stripe size on HP-UX 11.11?
I thought perhaps the lvdisplay command might have the info. Looking at typical output, I see that there is a Stripe Size. Would Lv Size correspond to the stripe width?
$ lvdisplay /dev/vgdb/lvol1
--- Logical volumes ---
LV Name /dev/vgdb/lvol1 VG Name /dev/vgdb LV Permission read/write LV Status available/syncd Mirror copies 0 Consistency Recovery MWC Schedule striped LV Size (Mbytes) 1198080 Current LE 4680 Allocated PE 4680 Stripes 6 Stripe Size (Kbytes) 1024 Bad block NONE Allocation strict IO Timeout (Seconds) default
I also looked at the vgdisplay command, part of which I have included below. Is there something here that is the equivalent of stripe size and stripe width?
- Volume groups ---
VG Name /dev/vgdb
VG Write Access read/write
VG Status available, exclusive
Max LV 16
Cur LV 5
Open LV 5
Max PV 255
Cur PV 36
Act PV 36
Max PE per PV 65535
VGDA 72
PE Size (Mbytes) 256
Total PE 14364
Alloc PE 14364
Free PE 0
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0
- Logical volumes --- LV Name /dev/vgdb/lvol1 LV Status available/syncd LV Size (Mbytes) 1198080 Current LE 4680 Allocated PE 4680 Used PV 12 .... ....
I realize that perhaps the best way to determine the optimal MBRC value with these file systesm would be to use the dd command and write a large datafile with different block size options to the filesystems. These database though have been up and running for quite a while and it's not possible to quiesce the systems and run benchmarks.
If anyone could confirm what I should be looking at with lgdisplay or vgdisplay, or can suggest another command, it would be greatly appreciated.
Thanks,
Lou Avrami
-- http://www.freelists.org/webpage/oracle-lReceived on Thu Sep 04 2008 - 15:49:18 CDT