Re: SATA-performance: Linux vs. FreeBSD

Jeffrey Hundstad
2007-02-13T20:23:28Z

Arjan van de Ven wrote:
>> The problem is: FreeBSD is fast, but lacks of some special drivers. Linux has
>> all drivers but access to harddisk is unpredictable and thus unreliable!
>> What can I do??
>>
>
>
> there's several tunables you can do;
> 1) increase /sys/block/<device>/queue/nr_requests
> the linux default is on the low side
> 2) investigate other elevators; cfq is great for interactive use but not
> so great for max throughput. you can do this by echo'ing "deadline"
> into /sys/block/<device>/scheduler
>

I'd suggest trying the noop scheduler with your ram based devices. I
don't see why these devices would need clever scheduling. ...but prove
me wrong if you will. I haven't tested this.

echo noop > /sys/block/<device>/queue/scheduler

If you don't need journaling EXT2 might be a good choice. But, I'd also
like to re-iterate the XFS filesystem recommendation given several times
now as well. There are many tunables that /may/ help during filesystem
creation. Block size (-b) set to it's maximum would prob. help.

If you're sure you can not encounter power issues:
mount -t xfs -o nobarrier /dev/<device> /mount-point

Here's some more general reading for ya:
Troubleshooting Linux Performance Issues:
http://www.phptr.com/articles/article.asp?p=481867&seqNum=2&rl=1

--
Jeffrey Hundstad