choosing a file system

[David Lang]

On Wed, 31 Dec 2008, Adam Tauno Williams wrote:

> On Wed, 2008-12-31 at 11:47 +0100, LALOT Dominique wrote:
>> Thanks for everybody. That was an interesting thread. Nobody seems to
>> use a NetApp appliance, may be due to NFS architecture problems.
>
> Personally, I'd never use NFS for anything.  Over the years I've had way
> to many NFS related problems on other things to ever want to try it
> again.

NFS has some very interesting capabilities and limitations. it's really bad for 
multiple processes writing to the same file (the cyrus* files for example) and 
for atomic actions (writing the message files for example)

there are ways that you can configure it that will work, but unless you already 
have a big NFS server you are probably much better off using a mechanism that 
makes the drives look more like local drives (SAN, iSCSI, etc) or try one of the 
cluster filesystems that has different tradeoffs than NFS does

>> I believe I'll look to ext4 that seemed to be available in last
>> kernel, and also to Solaris, but we are not enough to support another
>> OS.
>
> We've used Cyrus on XFS for almost a years, no problems.
>
> In regards to ext3 I'd pay attention to the vintage of problem reports
> and performance issues;  ext3 of several years ago is not the ext3 of
> today, many improvements have been made.  "data=writeback" mode can help
> performance quite a bit, as well as enabling "dir_index" if it isn't
> already (did it ever become the default?).  The periodic fsck can also
> be disabled via tune2fs.   I only point this out since, if you already
> have any ext3 setup,  trying the above are all painless and might buy
> you something.

it's definantly worth testing different filesystems. I last did a test about two 
years ago and confirmed XFS as my choice. I have one instance of cyrus still 
running on ext3 and I definantly see it as a user in the performance.

David Lang