Incidentally, this is something that is being focussed on as part of the upcoming release [1].
[1] https://cwiki.apache.org/confluence/x/v5YTAg On Tue, Nov 05, 2013 at 10:42:58PM +0000, Marty Sweet wrote: > The issue with plain MySQL replication (espically in master-master) is that > a failed query will stop replication. A good example of this is when an > record is added onto each master at the same time (within a second), say a > new record which gets the same primary key and replication will stop, on > both hosts. That then leaves a split brain situation when you have one > master writing its own data and another writing to itself, all with > identical primary keys. Absolute nightmare. This can how ever be migrated > with the methods the OP mentioned (I assume - but don't have experience of). > > I don't think file curroption is much of an issue with DRDB, but you can > only have one host write to it at anyone time (limitation of file system > used), which makes the master-slave or master-backup setup ideal when > coupled with HA service management software such as Pacemaker. You then > have the database files in both places without the dreaded MySQL > replication stories. > > I think the main question lyes with if the cloud admin wants a > simple redundant setup or a load balanced service - it may also we worth > writing some documentation for this to help future installations, although > they will have to be detailed. > > I have never used Percona/MariaDB, does it resolve the master-master issues > I mentioned earlier? > > Marty > > On Tuesday, November 5, 2013, Adrian Lewis wrote: > > > Seems like the Percona solution also uses Galera for their multi-master > > cluster. Starting to wonder whether to go MariaDB-Galera now. Tempted just > > to leave it as master slave replicated on MySQL though. Scale really not > > an issue right now. Ho hum, fun to be had if I had the time to play. > > > > Assuming no Galera (with either MySQL/Percona/MariaDB) and just using > > Centos version of MySQL - does anyone have any input as to whether to go > > for replicating between two hosts using DRBD vs native MySQL replication? > > I get the impression that MySQL replication is an eventually-consistent > > near-realtime kind of replication whereas DRBD can be set to be completely > > synchronous replication. MySQL replication just seems a lot less fiddly > > than using DRBD and DRBD would replicate file corruption that MySQL > > replication would be largely safe from. > > > > -----Original Message----- > > From: Patrick Miller [mailto:patrick.mil...@sungard.com <javascript:;>] > > Sent: 05 November 2013 21:51 > > To: users@cloudstack.apache.org <javascript:;> > > Subject: Re: Multi-master MySQL Setup > > > > Take a look at the percona [1] implementation of mysql and there clustered > > version. > > Round robin reads and writes supported. > > > > 1] http://www.percona.com/ > > > > Patrick > > > > > > On Tue, Nov 5, 2013 at 9:55 AM, Adrian Lewis > > <adr...@alsiconsulting.co.uk <javascript:;>>wrote: > > > > > Hi Marty/Nux!, > > > > > > Thanks for the feedback - sounds like multi-master is not a good thing > > > then! Load will likely be very small for at least the next 6 months > > > but I figured that it was one of those things that could be set easily > > > now (still setting up) that I might appreciate later. > > > > > > Based on both your responses, I think I'll just leave it well alone! > > > Need to get to grips with pacemaker/corosync anyway for other reasons > > > so I'll just try that with either DRBD replication or MySQL replication. > > > > > > Cheers, > > > > > > Adrian > > > > > > -----Original Message----- > > > From: Marty Sweet [mailto:msweet....@gmail.com <javascript:;>] > > > Sent: 05 November 2013 17:23 > > > To: users@cloudstack.apache.org <javascript:;> > > > Subject: Re: Multi-master MySQL Setup > > > > > > Others may have had more success with this but from experience of > > > MySQL in multi-master setups I would avoid this entirely. > > > > > > A common setup is using DRDB to provide a master/slave: > > > Management 1 (MySQL Master) w/ virtual IP Management 2 (MySQL Slave) > > > > > > HA IP Address (for agents/services requiring DB write) which is > > > assigned to the master (using Pacemaker). > > > > > > You can then send web management client to the HA IP Address as well. > > > > > > It may be worth considering if you need load balancing, depending on > > > your setup - what loads are you experiencing? > > > > > > Marty > > > > > > > > > > > > On Tue, Nov 5, 2013 at 5:13 PM, Adrian Lewis > > > <adr...@alsiconsulting.co.uk <javascript:;>>wrote: > > > > > > > Hi All, > > > > > > > > > > > > > > > > Just wondering if anyone is using a MySQL multi-master configuration > > > > with auto_increment_offset (e.g.10) and auto_increment_increment (1 > > > > for server 1, 2 for server 2 etc)? Does it work? Does anyone know a > > > > reason why it doesn't or wouldn't work? Is there anything from an > > > > application point of view that could/would trip up CS if > > > > auto_increment values are set as more than 1? > > > > > > > > > > > > > > > > Not planning on deploying multimaster just yet but if I at least > > > > start with an auto_increment of 10, I'd have the option of adding a > > > > second master later and being able to load-balance more effectively. > > > > > > > > > > > > > > > > Thanks in advance, > > > > > > > > > > > > > > > > Adrian > > > > > > > > > > > > -- Prasanna., ------------------------ Powered by BigRock.com
