Perdormance down on last build

[mikep]

Hello, I've just updated our SAN with the last build where irqbalance work properly. No changes had been done to config and I see a performance down in all our dd tests over iscsi. Looking at logs I can see this performance decrease too:

This are the hdparm values before the update:
*-----------------------------------------------------------------------------*
hdparm -t /dev/sda
*-----------------------------------------------------------------------------*


/dev/sda:
Timing buffered disk reads: 1682 MB in 3.00 seconds = 560.45 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sda
*-----------------------------------------------------------------------------*


/dev/sda:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sdb
*-----------------------------------------------------------------------------*


/dev/sdb:
Timing buffered disk reads: 800 MB in 3.02 seconds = 264.71 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sdb
*-----------------------------------------------------------------------------*


/dev/sdb:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sdc
*-----------------------------------------------------------------------------*


/dev/sdc:
Timing buffered disk reads: 742 MB in 3.01 seconds = 246.87 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sdc
*-----------------------------------------------------------------------------*


/dev/sdc:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sdd
*-----------------------------------------------------------------------------*


/dev/sdd:
Timing buffered disk reads: 1576 MB in 3.00 seconds = 524.89 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sdd
*-----------------------------------------------------------------------------*


/dev/sdd:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sdf
*-----------------------------------------------------------------------------*


/dev/sdf:
Timing buffered disk reads: 544 MB in 3.00 seconds = 181.13 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sdf
*-----------------------------------------------------------------------------*


/dev/sdf:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sde
*-----------------------------------------------------------------------------*


/dev/sde:
Timing buffered disk reads: 800 MB in 3.00 seconds = 266.63 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sde
*-----------------------------------------------------------------------------*


/dev/sde:

And this are the ones after the update:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sda
*-----------------------------------------------------------------------------*


/dev/sda:
Timing buffered disk reads: 1504 MB in 3.00 seconds = 501.24 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sda
*-----------------------------------------------------------------------------*


/dev/sda:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sdb
*-----------------------------------------------------------------------------*


/dev/sdb:
Timing buffered disk reads: 1556 MB in 3.01 seconds = 516.39 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sdb
*-----------------------------------------------------------------------------*


/dev/sdb:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sdc
*-----------------------------------------------------------------------------*


/dev/sdc:
Timing buffered disk reads: 824 MB in 3.00 seconds = 274.56 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sdc
*-----------------------------------------------------------------------------*


/dev/sdc:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sdd
*-----------------------------------------------------------------------------*


/dev/sdd:
Timing buffered disk reads: 746 MB in 3.00 seconds = 248.45 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sdd
*-----------------------------------------------------------------------------*


/dev/sdd:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sde
*-----------------------------------------------------------------------------*


/dev/sde:
Timing buffered disk reads: 284 MB in 3.00 seconds = 94.51 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sde
*-----------------------------------------------------------------------------*


/dev/sde:

*-----------------------------------------------------------------------------*
hdparm -t /dev/sdf
*-----------------------------------------------------------------------------*


/dev/sdf:
Timing buffered disk reads: 632 MB in 3.01 seconds = 210.01 MB/sec

*-----------------------------------------------------------------------------*
hdparm -i /dev/sdf
*-----------------------------------------------------------------------------*


/dev/sdf:

Any ideas? Controller is Adaptec 6805. I was expecting the opposite to this situacion.

Regards

[SeanLeyne]

@mikep, please trim down your posts... there is a lot of whitespace/"bumpf" in your posting which could have been trimmed to make the post more readable and consise.

[To-P]

The hdparm tool can show the read performance speed but it varies depending on
the current system load.
A better way to test the performance will be to use the disk performance test
tool from the DSS V6 console which use "dd" command to gather the measurement
results to see how fast your RAID unit works. Don't do the write performance
tests as they are only possible on a RAID unit where no vg is created.
To access the disk performance tool from the DSS V6 console, press ctrl + alt +
W -> System benchmarks -> Disk performance test.

You can have a look at some of our KB articles about RAID performance tuning:

Information on Configuring for Optimal RAID Performance
http://kb.open-e.com/Information-on-...ance_1323.html

System performance, and RAID BIOS settings.
http://kb.open-e.com/System-performa...ings_1283.html

[strategist922]

The hdparm tool can show the read performance speed but it varies depending on
the current system load.
A better way to test the performance will be to use the disk performance test
tool from the DSS V6 console which use "dd" command to gather the measurement
results to see how fast your RAID unit works. Don't do the write performance
tests as they are only possible on a RAID unit where no vg is created.
To access the disk performance tool from the DSS V6 console, press ctrl + alt +
W -> System benchmarks -> Disk performance test.

You can have a look at some of our KB articles about RAID performance tuning:

Information on Configuring for Optimal RAID Performance
http://kb.open-e.com/Information-on-...ance_1323.html

System performance, and RAID BIOS settings.
http://kb.open-e.com/System-performa...ings_1283.html

Thanks for your information.
Could you please give some suggestion about how to optimize the Areca ARC-1680 / ARC-1880 series RAID Card ?

Best Regards!