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* Need some help analyzing some benchmarks
@ 2011-02-06 08:04 Benjamin Krajmalnik <kraj@servoyant.com>
0 siblings, 1 reply; 2+ messages in thread
From: Benjamin Krajmalnik @ 2011-02-06 08:04 UTC (permalink / raw)
To: pgsql-performance
Before I deploy some new servers, I figured I would do some
benchmarking.
Server is a Dual E5620, 96GB RAM, 16 x 450GB SAS(15K) drives.
Controller is an Areca 1680 with 2GB RAM and battery backup.
So far I have only run bonie++ since each cycle is quite long (writing
192GB).
My data partition is 12 drives in RAID 1+0 (2.7TB) running UFS2.
Vfs.read_max has been set to 32, and no other tuning has been done.
Files system is not mounted with noatime at this point.
Below are the results:
db1# bonnie++ -d /usr/local/pgsql -c 4 -n 2:10000000:1000000:64 -u pgsql
Version 1.96 ------Sequential Output------ --Sequential Input-
--Random-
Concurrency 4 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
db1.stackdump. 192G 860 99 213731 52 28518 45 1079 70 155479 34
49.9 12
Latency 10008us 2385ms 1190ms 457ms 2152ms
231ms
Version 1.96 ------Sequential Create------ --------Random
Create--------
db1.stackdump.local -Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files:max:min /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
/sec %CP
2:10000000:1000000/64 49 33 128 96 277 97 57 39 130 90
275 97
Latency 660ms 13954us 13003us 904ms 334ms
13365us
Not having anything to compare it to, I do not know if these are decent
numbers or not - they are definitely slower than a similar setup which
was posted recently using XFS on Linux, but I have not found anything
in FreeBSD using UFS2 to compare it to. What strikes me in particular
is that the write performance is higher than the read performance - I
would have intuitively expected it to be the other way around.
My log partition is a RAID1, same drives. Performance follows:
Version 1.96 ------Sequential Output------ --Sequential Input-
--Random-
Concurrency 4 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
db1.stackdump. 192G 861 99 117023 28 20142 43 359 23 109719 24
419.5 12
Latency 9890us 13227ms 8944ms 3623ms 2236ms
252ms
Version 1.96 ------Sequential Create------ --------Random
Create--------
db1.stackdump.local -Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files:max:min /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
/sec %CP
2:10000000:1000000/64 24 16 121 93 276 97 22 15 134 93
275 97
Latency 4070ms 14029us 13079us 15016ms 573ms
13369us
After seeing these results, I decided to download the areca cli and
check the actual setup
Info from the RAID controller follows:
CLI> sys info
The System Information
===========================================
Main Processor : 1200MHz
CPU ICache Size : 32KB
CPU DCache Size : 32KB
CPU SCache Size : 512KB
System Memory : 2048MB/533MHz/ECC
Firmware Version : V1.48 2010-10-21
BOOT ROM Version : V1.48 2010-01-04
Serial Number : Y051CABVAR600825
Controller Name : ARC-1680
Current IP Address : 192.168.1.100
CLI> rsf info raid=2
Raid Set Information
===========================================
Raid Set Name : Raid Set # 001
Member Disks : 12
Total Raw Capacity : 5400.0GB
Free Raw Capacity : 0.0GB
Min Member Disk Size : 450.0GB
Raid Set State : Normal
CLI> vsf info vol=2
Volume Set Information
===========================================
Volume Set Name : ARC-1680-VOL#001
Raid Set Name : Raid Set # 001
Volume Capacity : 2700.0GB
SCSI Ch/Id/Lun : 00/00/01
Raid Level : Raid1+0
Stripe Size : 8K
Member Disks : 12
Cache Mode : Write Back
Tagged Queuing : Enabled
Volume State : Normal
===========================================
Having done this, I noticed that the stripe size is configured to 8K.
I am thinking the problem may be due to the stripe size. I had asked
the vendor to set up the file system for these two arrays with 8K
blocks, and I believe they may have misunderstood my request and set the
stripe size to 8K. I assume increasing the stripe size will improve the
performance.
What stripe sizes are you typically using? I was planning on setting it
up with a 64K stripe size.
TIA,
Benjamin
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Need some help analyzing some benchmarks
@ 2011-02-07 01:36 Greg Smith <greg@2ndquadrant.com>
parent: Benjamin Krajmalnik <kraj@servoyant.com>
0 siblings, 0 replies; 2+ messages in thread
From: Greg Smith @ 2011-02-07 01:36 UTC (permalink / raw)
To: Benjamin Krajmalnik <kraj@servoyant.com>; +Cc: pgsql-performance
Benjamin Krajmalnik wrote:
>
> My data partition is 12 drives in RAID 1+0 (2.7TB) running UFS2.
> Vfs.read_max has been set to 32, and no other tuning has been done...
>
> Not having anything to compare it to, I do not know if these are
> decent numbers or not -- they are definitely slower than a similar
> setup which was posted recently using XFS on Linux, but I have not
> found anything in FreeBSD using UFS2 to compare it to. What strikes
> me in particular is that the write performance is higher than the read
> performance -- I would have intuitively expected it to be the other
> way around.
>
Generally write speed higher than read means that volume read-ahead
still isn't high enough for the OS to keep the disk completely busy.
Try increasing read_max further; I haven't done many such tests on
FreeBSD, but as far as I know settings of 128 and 256 are generally
where read performance peaks on that OS. You should see sequential read
speed go up as you increase that parameter, eventually levelling off.
When you reach that point you've found the right setting.
--
Greg Smith 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books
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2011-02-06 08:04 Need some help analyzing some benchmarks Benjamin Krajmalnik <kraj@servoyant.com>
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