status of dir_index in 2.4 kernels ?

[Adam Cassar]

I have had some issues with htree under high load but I believe that 
this is fixed in newer 2.6 kernels.



Jakob Curdes wrote:

> 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
>
>        http://thunk.org/tytso/linux/extfs-2.4-update/
>
> 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
>
>     http://e2fsprogs.sourceforge.net/
>
> 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
>
> https://www.redhat.com/archives/ext3-users/2004-September/msg00025.html
>
> 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,
>
> Jakob Curdes
>
>
>
>
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