Re: [squid-users] Optimal cache_dir L2 value for ReiserFS?

wojtek@3miasto.net wrote:

>>I was advised some time ago that for the Linux ext2 file system a
>>cache_dir value of L2=254 was more efficient than that of L2=256. Is
>>
> shouldn't make big difference.
>
>
>>there a similar performance consideration for the ReiserFS file system?
>>
>
> NO. in reiserfs doing something like 1 4096 is even better.

Wrong. While it was the expected behavior, I did a large number of
benchmarks about 6 months ago that proved this theory very very wrong
when using an async i/o Squid compile--Nikita's tests also reinforced
this. Performance breaks down badly when a large number of directories
and files is used with ReiserFS. It was theorized that it has to do
with directory level locking that, at the time, was not expected to be
fixed until Linux 2.5/ReiserFS 4. As far as I know this has not changed
in the least in the past 6 months.

If you are using a non-async i/o compile, then yes, using one large top
level directory is better...but it is definitely not the fastest
configuration for ReiserFS and Squid.

The current standard of 256 is quite a reasonable number, performing
just about as well as ReiserFS can.

This was all discussed extensively on the ReiserFS list. A search will
likely turn up all the information you need on this.
                                   --
                      Joe Cooper <joe@swelltech.com>
                  Affordable Web Caching Proxy Appliances
                         http://www.swelltech.com
Received on Wed May 23 2001 - 12:53:20 MDT