On rereading this, I see that I did not mention that I'm referring to the requirement you mention for the replicated database box to be at least as powerful as the production database box.
> -----Original Message----- > From: Van Mittal-Henkle [mailto:va...@grameenfoundation.org] > Sent: Friday, July 10, 2009 12:57 PM > To: A good place to start for users or folks new to Mifos. > Subject: Re: [Mifos-users] MySQL > > Todd, > > This is great information! And we're already feeding this into plans > related to replication. > > One question regarding this-- you specifically mention this is the case > for MySQL 5.0. Is it also the case for 5.1 or is the situation > different for 5.1? I remember seeing some mention in the 5.1 release > notes regarding performance and replication. > > Thanks, > --Van > > > -----Original Message----- > > From: Todd Farmer [mailto:t...@fivefarmers.com] > > Sent: Thursday, July 09, 2009 9:31 PM > > To: A good place to start for users or folks new to Mifos. > > Subject: Re: [Mifos-users] MySQL > > > > Hi, > > > > Adam Feuer wrote, On 7/9/2009 8:00 PM: > > > >From my experience (at Amazon and other places) one-direction > MySQL > > > replication overhead on the master (production) database is > > > negligible. The server is only writing binary logs to the network, > > > something it already does to disk. This uses only small amounts of > > CPU > > > and a small amount of network bandwidth. > > > > > > Also, since reporting load will now go to the slave database as > Beth > > > says, load on the master should be much lighter. > > > > > Just agreeing with Adam, here. The major impact isn't replication > > (shipping the binary logs to another server), but rather the binary > > logging itself (that's the focus of the blog entries in the original > > email). If you already have binary logging enabled, setting up > > replication is no big deal, performance-wise. > > > > That said, there are ways to reduce the performance hit that binary > > logging entails (disabling XA transactions - not used in most > > applications - is a good start, as using a different physical disk > for > > binary logs). > > > > One performance element which sometimes hits people new to MySQL > > replication is actually the performance of the slave. It's important > > to > > have a machine that is at *least* as powerful as the master. This is > > because MySQL replication (in 5.0 and earlier) takes the DML > statements > > being issued by multiple client threads, which the slave then > executes > > in a single thread. If you have 5 different long-running DML > > statements > > affecting different tables, they can execute simultaneously on the > > master, but are executed serially on the slave. And any statement > > which > > is slow on the master will be similarly slow on the slave - the > > statement still has to go through the exact same process on the slave > > as > > it did on the master (parsing, optimizing, locking, execution, etc.). > > > > People sometimes fall into a trap where they assume that the master > is > > doing all the heavy lifting, and the slave can be a less powerful > > machine. This isn't true - it's doing all the work the master is > > doing, > > except in a single thread while the master might have work spread > > across > > multiple concurrent threads. Plus it has to deal with the read > volume > > that has been offloaded to the slave. > > > > Best regards, > > > > Todd Farmer > > > > > > > ----------------------------------------------------------------------- > > ------- > > Enter the BlackBerry Developer Challenge > > This is your chance to win up to $100,000 in prizes! For a limited > > time, > > vendors submitting new applications to BlackBerry App World(TM) will > > have > > the opportunity to enter the BlackBerry Developer Challenge. See full > > prize > > details at: http://p.sf.net/sfu/Challenge > > _______________________________________________ > > Mifos-users mailing list > > Mifos-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/mifos-users > > > ----------------------------------------------------------------------- > ------- > Enter the BlackBerry Developer Challenge > This is your chance to win up to $100,000 in prizes! For a limited > time, > vendors submitting new applications to BlackBerry App World(TM) will > have > the opportunity to enter the BlackBerry Developer Challenge. See full > prize > details at: http://p.sf.net/sfu/Challenge > _______________________________________________ > Mifos-users mailing list > Mifos-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/mifos-users ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ Mifos-users mailing list Mifos-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mifos-users
