OT: BEWARE filesystem changes!

[Fairlight]

Just a general heads-up.  If anyone is storing -large- amounts of files on
an older system using reiserfs, be -very- careful when migrating to ext4.

Reiserfs doesn't actually have a hard inode limit, as far as I can tell.
However, ext4 does.  This becomes problematic when someone has stored over
6.5 million inodes on the old system, you go to do an rsync, and run out of
"disk space" at only 57% of used -space-.  However, you've entirely
exhausted the inode table for the filesystem.

Even more fun, reiserfs not only doesn't have limits, it doesn't bother to
keep track of how many inodes there are.  If you weren't using LVM on the
originating system, it's a complete pain to try and find out how many are
in use.

There are ways to tweak the ext4 filesystem to increase the inode ratio at
creation, but you cannot simply allocate/add more inodes later.  I'm in the
process of finding out if that number grows if you resize the partition, or
barring that, add a new volume via lvm.  No idea yet.  I'd call the whole
thing a bad design decision, but I didn't write ext4.

Just be aware of the issue.  I've never personally seen it happen before
today, but I'm not the only one to be bitten by it.

Common wisdom says avoid more than 500 files in a directory, for
performance's sake.  Unfortunately, a directory heirarchy which breaks
things down by year, month, day, hour, minute uses a -hell- of a lot of
inodes before it even gets to the files underneath.  (Think Postfix style
heirarchy, but applied to files being stored and referenced by filePro
records, which is exactly what someone did, and how it's relevant.)

Just a heads-up.

mark->
-- 
Fairlight Consulting
http://www.fairlite.com
fairlite at fairlite.com
(502) 509-3840