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New Question: Cluster Overall Memory Requirements (compared to multiple stand-alone nodes)
A new question has been asked in "Galera" by getreal:
Maybe I'm just missing it somewhere on the site, but I'm trying to find a way to contrast overall memory requirements for a Galera cluster compared to that of stand-alone mySQL instances. In my profession we build servers that are typically 32GB overall memory running an instance of mySQL within, in which we hand 16GB to innodb_buffer_pool_size (the actually size of the mySQL database files is upwards of four times that). The server does other things by the way (a 6 GB JVM is also loaded). Our buffer pool hit rate is typically a nice high number (over 99%) with that 16GB allocated. So let's take a simple scenario - 6 of my stand-alone servers are going to evolve to MariaDB + Galera cluster. I completely realize we need 3 nodes minimum on the Galera side, and I realize we now are accommodating about 6 x 64GB of former mySQL database files (as long as we presume the database files overall size in mariaDB is about the same as that of mySQL). So I've got 384 GB of database f
iles, and let's suppose I want to replace this with a 3 node mariaDB+Galera cluster. I know that 384 GB has to be replicated amongst those three nodes, storage sizing is not so complex, and I know I can probably get enough CPU under these node with 4 vCPUs. But my question is more so around innodb_buffer_pool size for each node. Do I need to run 6 x 16 GB = 96 GB for innodb_buffer_pool_size in each node of that Galera cluster (essentially the same ratio 1:4 as I did in mySQL instances with my stand-alone servers) ? Any help appreciated.
To view or answer this question please visit: http://mariadb.com/kb/en/cluster-overall-memory-requirements-compared-to-multiple-stand-alone-nodes/