[Gluster-users] Bug 246

[Mike Cardwell]

On 24/09/2009 10:18, Pavan Vilas Sondur wrote:

>> Anybody knows if this bug effect Gluster as MySQL data directory in
>> MySQL cluster setup in gluster distirbute only setup(no replicate) ?
>>
>> and if there any timeline regarding this bug , unable to lock files
>> for mysql clusters is a big issue .

 > MySQL does work on GlusterFS very well. The issue in Bug 246 is that
 > two mysql server processes do not work well if they share the same
 > (even mirrored) data directories. Since this is a MySQL limitation - 
 > Bug 246 has been closed. However feel free to report to us if MySQL
 > does work with shared data directories between he server processes
 > elsewhere.

I have some experience of pointing two instances of MySQL at the same 
shared storage when using GFS, but I have never tried it with Gluster. 
It will work with GFS but you have to use external locking, turn off the 
query cache and avoid innodb...

The external locking is required otherwise each instance of MySQL will 
internally keep records of what tables/rows are locked. With external 
locking turned on, it uses file locks instead.

The query cache needs to be turned off because when one instance of 
MySQL updates a table, the other one doesn't know to clear its cache.

-- 
Mike Cardwell - IT Consultant and LAMP developer
Cardwell IT Ltd. (UK Reg'd Company #06920226) http://cardwellit.com/