OT: BEWARE filesystem changes!

[Bill Campbell]

On Sat, Mar 29, 2014, Fairlight wrote:
>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.

Interesting info although it's been over a decade since I used
reiserfs for anything, having had problems with data loss using
in (not to mention the author's problems :-).

....
>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.)

Probably the largest user of inodes on many of our systems are
the Maildir mail stores with a file per message.

Now if Linux had good support for zfs...

Bill
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