7.1-PRERELEASE: arcmsr write performance problem

[Mike Tancsa]

At 05:29 PM 12/15/2008, Paul MacKenzie wrote:

>The next thing I am doing is going to be removing the QUOTA feature 
>to see if this has any bearing
>on this problem. It does not appear to be even writing at a heavy 
>load as you can see (almost
>nothing) but the processes are mostly in UFS when it spirals out of control.


Whats strange is that the output from gstat shows the disks hardly 
active at all.... Yet why is the syncer at 100% ?  Do you have write 
caching disabled on the array ?  What does the raw throughput look 
like to the disks ?  e.g. if you try a simple dd if=/dev/zero 
of=/var/tmp bs=1024k count=1000  ?

>I moved the processing of amavisd-new into a memory drive to at 
>least take that off the IO and this
>seems to have helped a bit. There is not a lot of mail going through 
>the system but every little bit
>helps. I suspect this is one other reason that is bringing the 
>problem to the forefront as
>amavisd-new can use the disks a bit to process each e-mail.


Is the high load average simply a function of processes blocking on 
network io ? On our av/spam scanners for example show a high load avg 
because there are many processes waiting on network io to complete 
(e.g. talking to RBL lists, waiting for DCC servers to complete etc)

Also, is it really related to the arcmsr driver ? i.e. if you did the 
same tasks on a single IDE drive, is the performance profile going to 
be the same ?

         ---Mike