status of dir_index in 2.4 kernels ?
jc at info-systems.de
Fri Sep 24 07:13:34 UTC 2004
Ok, I try to summarize what I gathered from this and the earlier thread
to help other "htree newbies"
(Please correct my statements if necessary):
- To use htree enabled ext - Filesystems in 2.4 kernels, you need
a) a htree enabled kernel; patch against 2.4.21 can be found at
Curiously enough, I colud not apply this patch against a clean 2.4.27
tree - is there anything special to be aware of ??
b) the current e2fsprogs which you can get from
c) you have to enable dir_index on the filesystem with
<> # umount /dev/xyz
# tune2fs -O dir_index /dev/xyz
# e2fsck -fD /dev/xyz
# mount /dev/xyz
d) The performance of the htree indexed filesystem depends on the usage
by the userspace programs; if they open all files in a directory after
gaining directory information with readdir() the performance is worse
than with a vanilla ext3 fs, at least if we have many files in that
directory [as it is the case with maildir structures]. This can be
cured by an additional userspace library which can be found in the message
e) One question remains open : Is the htree feature in its current state
considered stable enough to be used in production systems ?
I read some reports on filesystem corruption, but most of these applied
to older versions of htree. Are there differences between the 2.6
implementation and the 2.4 backport ?
Thank you for comments,
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