squid-fs some very basic info

Hi

(apologies for mailing all sorts of seperate messages - they are all the
mail that has been sitting on my laptop ready to send for days and days
now...)

-------
Hi all

Compared to the pretty technical thread that has been going on recently
this is a pretty pitiful note, but it may be worth putting in the Squid
Releas notes/FAQ sometime in the future. It may also be clueless :)

I was reading linux-kernel the other day and saw a problem where someone
had changed the block size, and could no longer make very large files on that
device. The problem is that there are a maximum number of indirection
blocks in the fs code, and since his block size was small it meant that he
needed lots of indirect blocks to maintain a file of that length.

I just realized that the number of 'indirect' block pointers could be reduced on
Linux's ext2 filesystem by specifying a larger block size, and this has an
if the squid-fs stuff seems worthwhile.

If we have a really large file (on a filesystem, not on an actual /dev
entry...) a very large block size would reduce the number of indirect
blocks that we need. People should re-format their cache store filesystem
to have a very large block size.

I don't know if putting Squid-FS on a /dev/ entry is such a good idea. I
believe that we changed our Sybase (Solaris) setup to store the database on
a raw device. We found that the IO rate according to iostat dropped
dramatically (at least for certain types of accesses...).
Once Squid-FS is happy and running I would be interested to see if that is
the case.

-------

Oskar

---
"Haven't slept at all. I don't see why people insist on sleeping. You feel
so much better if you don't. And how can anyone want to lose a minute -
a single minute of being alive?"				-- Think Twice