best filesystem for imap server

[David Lang]

On Wed, 1 Dec 2004, Jim Miller wrote:

> I feel that XFS is a bad choice since it is not a 'truly' journaled file
> system.  If you have a power failure/system crash/lockup, etc., etc. You
> could very easily end up with a corrupt file system -- XFS doesn't write out
> to the disks immediately (caching unwritten data to memory).  EXT3 is
> journaled but very slow.  ReiserFS is a better choice for a journaled file
> system and if you can hold off until all the bugs are worked out, Reiser4FS
> would be the best choice (IMHO).

note that most journaling filesystems journal the metadata, not the file 
data (and ext3 does this as well by default, but it has a mode to enable 
journaling everything)

and actually ext3 had the option to journal everything becouse in the 
initial implementation the peopel writing the code couldn't seperate the 
two types of data so to simplify things they journaled everything.

the reason that not everything is journaled is a simple performance issue. 
having to write the data to the journal, read it from the journal and 
write it to the final location, then update the journal requires a LOT 
more IO bandwidth then if you just do this for the metadata.

personally I have trouble trusting reiserfs ever since it was revealed 
that one reason that it was doing so well on benchmarks is that it delaye 
up to 30 seconds before writing anything to disk so in many cases the 
benchmark was completed before any disk activity took place. This has been 
changed, but it leaves a bad taste behind.

also note that if you are useing IDE drives you have no way of really 
knowing when the data has hit the platter (as opposed to just being in the 
buffer of the drive) as many of the drives will lie to you and tell you 
the write is complete once it hits the buffers.

David Lang

>
>
> Jim
>
>
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