[Linux-cluster] IMAP server clustering ...

[Michael Gale]

But would you even need the GFS file system then ? Could each box just 
be accessing a reiserfs via the FC ? and let the application take care 
of the "locking" ?

Michael.



Lon Hohberger wrote:
> On Thu, 2004-10-28 at 13:14 -0600, Michael Gale wrote:
> 
> 
>>2. GFS does not protect against data corruption as it is the 
>>applications responsibility to making sure that data written to a file 
>>is complete.
> 
> 
>>3. Maildir format does not require file locking and works great over NFS 
>>  except for the speed issue of course.
> 
> 
> "Not requiring file locking" is not the same as "not requiring any
> locking".
> 
> 
>>If you use Courier IMAP every body can access the same directories / 
>>partitions at the same time because file locking is not an issue.
>>"IMAP_USELOCKS
>>
>>     This setting in /usr/lib/courier/etc/imapd must be enabled. This 
>>setting uses dot-lock files to synchronize updates to folder indexes 
>>between multiple IMAP clients that have the same folder opened.
> 
> 
>>     This setting is safe to use with NFS, as it does not use actual 
>>file locking calls, and does not require the services of the problematic 
>>NFS lock"
> 
> 
> Instead of file locking, they're doing dot-locking.
> 
> I suspect GFS would work fine if you had the above setting enabled;
> creating a file (e.g. a dot-lock) should be atomic across the cluster.
> 
> -- Lon
> 
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> 

-- 
Michael Gale
Lan Administrator
Utilitran Corp.

The best part is when the people who know the least are the ones ranting 
and raving.