On Friday 16 December 2005 15:50, Brenton Rothchild wrote: > Anyone feel free to correct me, but I was just doing some > reading on active-active MySQL + GFS last night, and > I think such an arrangement might be possible to a degree. > > From what I can read in the MySQL documentation, > http://dev.mysql.com/doc/refman/5.0/en/system.html > http://dev.mysql.com/doc/refman/4.1/en/system.html > > MySQL can use external file locking via flock() calls, > although the 4.1 page describes that file locking is turned off > by default "because Linux file locking is not yet safe" via > a compile-time option "--skip-external-locking". > > The 5.0 page doesn't warn against using external file locking > to that degree, but the option to use locking is still > disabled via the "--skip-external-locking" flag. > > There are also some caveats to using the --external-locking option > in MySQL. See the documentation for "--external-locking" in > http://dev.mysql.com/doc/refman/4.1/en/server-options.html > http://dev.mysql.com/doc/refman/5.0/en/server-options.html > > Now, on the GFS side, locking via flock() and fcntl()-based > locks appear to be supported cluster-wide from this thread, > http://www.redhat.com/archives/linux-cluster/2004-October/msg00311.html > > So, putting them together, if GFS supports file locking, > and MySQL can use file locking to support multiple instances > accessing the same files, an active-active MySQL set up should work. > > I, too, and using a test cluster with GFS + iSCSI at this point, > and I plan to test MySQL 4.x and 5.x versions on it soon to > see what happens. I really hope it works out under the loads > we want to test. :) > > Like I said, anyone else feel free to correct me - I'm still > just getting started with RHCS/GFS/etc. at this point. > > -Brenton Rothchild > > Omer Faruk Sen wrote: > > Hi, > > > > I want to install a mysql cluster. But I want to ask which path do I have > > to follow? Or there is any special precautions that I have to take care > > before and after installing mysql and redhat cluster suite. > > > > My first impression is to install 2 node cluster it is better for me to > > use GFS and a iscsi solution for a cheaper solution. But I have > > understood from my readings that I can't setup an active-active mysql > > cluster using redhat cluster + GFS. Because one node must be locked for > > writing. Thus I think installing the second server for writing may be > > just for > > availability not for combining 2 machines power ( I mean using > > active-acvtive). > > > > Then I think to install 2 machines for write (one is standby) on a redhat > > cluster using GFS on a ISCSI system and adding a number of machines that > > use the same GFS partition for msqyl read operations is what I have to > > follow .. right? > > > > PS: By the way can you give me an URL that details mysql and redhat > > cluster + gfs installation? Or is there any ? > > -- > > Linux-cluster@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/linux-cluster It is possible to use mysql on shared storage with enabled external locking and also disabling the query cache and few other things: enable-locking query_cache_wlock_invalidate query_cache_size= 0 query_cache_type= 0 delay_key_write = OFF flush in mysqld section this configuration worked for my 10 node cluster . -- ------------------------------------------------------------------------- When you finally buy enough memory, you will not have enough disk space. -- Murphy's Computer Laws n°3 ------------------------------------------------------------------------- -- Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
