XFS tune to adaptec ASR71605

[Steve Brooks]

> Yup, they're... weird :) Write speed is abysmal, but random seeks very
> high. Please try my settings so that we can compare the numbers more
> directly:
>
> bonnie++ -f -d ./ -n 50
>
> If you translate the output from my test file with bon_csv2
>
> Did you turn off write cache? did you tune the IO scheduler, read
> ahead, and queue length? Here are the settings I'm generally using
> with this type of controllers (for better sequential IO):
>
> echo none > /sys/block/sda/queue/scheduler
> echo 1024 > /sys/block/sda/queue/nr_requests
> echo 65536 > /sys/block/sda/queue/read_ahead_kb
>
> You can check the cache status in the output from
>
> arcconf getconfig 1
>
> If you didn't install arcconf, you definitely should :) If you turned
> off the write cache, be aware that this is not the expected mode of
> operation for modern RAID controllers... Go buy a ZMM if necessary.


Hi,

Yes the write speed is very poor.. I am running "bonnie++" again with your 
params but no sure how long it will take.

>  bonnie++ -f -d ./ -n 50

Will thisno be different for our two machines as it seems to generate 
other params depending on the size of the RAM. All ours have 64G RAM.


I disabled write cache on the controller as there is no ZMM flash backup 
module and it seems to be advised that way. I could enable it and try 
another test to see if that is a contribution to the poor write 
performance. I do have "arcconf" on all our adaptec raid machines.

I have not tuned the IO scheduler, read ahead, and queue length?  I guess 
I can try this.

> echo none > /sys/block/sda/queue/scheduler
> echo 1024 > /sys/block/sda/queue/nr_requests
> echo 65536 > /sys/block/sda/queue/read_ahead_kb

Will this need to be done after every reboot? I guess it could go in 
"/etc/rc.local" ?


Thanks, Steve