Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

Dear Adrian,
Well my conclusion that this is an IO problem came from the fact that I see
huge IO waits as the volume of traffic increase (with tools such as mpstat),
when using ramdisk there is no such issue.
I have configured the SSD drive with ext2, no journal, noatime. Used the
“noop” I/O scheduler.
In /etc/fstab
/dev/sdb1 /cache ext2 defaults,noatime 1 2

hdparm results:
hdparm -t /dev/sdb1

/dev/sdb1:
 Timing buffered disk reads: 304 MB in 3.01 seconds = 100.93 MB/sec

----
hdparm -T /dev/sdb1
/dev/sdb1:
 Timing cached reads:   4192 MB in  2.00 seconds = 2096.58 MB/sec
Any ideas?
Regards.
Adrian Chadd-3 wrote:
> 
> 2009/8/2 smaugadi <adi_at_binat.net.il>:
>>
>> Dear Adrian,
>> During the implementation we encountered issues with all kind of
>> variables
>> such as:
>> Limit of file descriptors (now the squid is using 204800).
>> TCP port range was low (increased to 1024 65535) TCP timers (changed
>> them)
>> The ip_conntrack and hash size were low (now 524288 262144 respectively)
>>
>> Now we are at a point that IO is the only issue.
> 
> What profiling have you done to support that? For example, one of the
> issues I had which looked like IO performance was actually because the
> controller was completely unhappy. Upgrading the firmware on the
> controller card signficantly increased performance.
> 
> But I think you need to post some further information about the
> problem. "IO" can be rooted in a lot of issues. :)
> 
> 
> Adrian
> 
> 
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