--- Henrik Nordstrom wrote: >
On Fri, 9 Apr 2004, ThE LinuX_KiD wrote:
>
> > I will lost performance if my Linux box are

> working
> > with "swapon" ?

>
> Disk layout is not relevant.
>
> Yes, you risk loosing performance if you have swap,
> as the OS then risks
> swapping out parts of Squid due to relatively low
> I/O pressure in certain
> situations which typically occurs during high load
> situations (where it is
> worst if this happens..)


the first time i built a high performance transparent
Squid cache (and i remember posting that query on this
list some 2yrs back) was when i was running it on SuSE
7.2 Pro with Squid-2.3 then Squid-2.4 and a
self-recompiled SuSE stock source-rpm 2.2.19-SMP
kernel..

i had a 512MB /swap partition, 512MB of RAM which i
gradually upgraded to 1.3GB, and a total of 72GB worth
of SCSI hard drive space..

what happenned was that my /swap was on and running,
but my system never ever did swap, even when the load
increased.. physical RAM utilisation went from 1.3GB
to as low as 2MB.. whenever RAM hit 2MB, it shot up to
3MB, and this cycle continued until either Squid did
its internal sanities, or i restarted the Squid
process, at which point memory was freed up to about
24MB.. and then continued to fall till 2MB, where it
rose back again to 3MB, and this went on and on and on
and on...

what's strange is that i never applied any tweaks to
the kernel or system in general to have this rather
peculiar (but very welcomed) performance.. the system,
during it's uptime till this day, has never touched
the /swap partition for even as much as a byte.. i
still find this fascinating.. and yet i have similar
systems running with the same software (save that the
kernel hasn't been recompiled) and those DO swap...

i would like to achieve this, but the difference is
that i will be running on a 2.4 kernel, and not a 2.2,
as is the previous Squid server, so am not sure how
good my chances are.. ..

is there a clear explanation as to why this is..?..

Regards,

Mark.





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