Thankx Amos, for the quick answer. This book is indeed old, Jan 2004. But
it was interesting to see this comment, because it discusses all the storage
schemes: ufs, aufs, diskd, coss & null. Perhaps he was only mentioning ufs.
I have a short question:
Duane also says to resize the L1 and L2 values in storage scheme to
reasonable values so that each folder holds just a few hundred files. I'm
using the default values, and my object count is 7M, making it a 3.3k+
objects per folder. Should I be concerned about this?
Regards
HASSAN
----- Original Message -----
From: "Amos Jeffries" <squid3@xxxxxxxxxxxxx>
To: "Nyamul Hassan" <mnhassan@xxxxxxx>
Cc: "Squid Users" <squid-users@xxxxxxxxxxxxxxx>
Sent: Sunday, November 30, 2008 10:11
Subject: Re: Number of Spindles
Nyamul Hassan wrote:
Hi,
I was reading through Duane Wessel's book, and I must say, it is a GREAT
book. If only I had read it earlier, my life would've been so much
better! :)
I was reading through Appendix D: Filesystem Performance benchmarks,
where Duane says the following:
"The primary purpose of these tests is to show that Squid's performance
doesn't increase in proportion to the number of disk drives. Excluding
other factors, you may be able to get better performance from three
systems with one disk drive each, rather than a single system with three
drives."
Isn't this contrary to what we've been seeing over and over again in the
forum, that increasing the number of spindles distributes disk IO, and
increases cache efficiency by avoiding io_wait for the CPU? Or is it
that, when you use SCSI U320 HDDs, your io_wait becomes a non issue, and
that is what Duane was referring to when he started the concluding line
with "Excluding other factors"?
Could the gurus in this forum please shed some light on this?
The books is rather old. From the days of Squid-2.5.
I think diskd was developed in Squid as a solution to that problem, then
AUFS came along to improve things even further as a native OS layer.
Plain old single-threaded UFS still displays many of the performance
issues mentioned.
Amos
--
Please be using
Current Stable Squid 2.7.STABLE5 or 3.0.STABLE10
Current Beta Squid 3.1.0.2
