Hi, You're very much correct about the nodes & HA - but that wasn't the question - The question was if 3 nodes are a must - and the answer is no - you can technically use 1 physical node. The fact it doesn't provide any redundancy is not MySQL specific, but true to any cluster of any kind :)
You are also correct about the indexes. As far as I can remember there is a script that analyzes existing databases and reports the amount of RAM needed to run MySQL cluster (it actually outputs the configuration directives needed, but you can easily calculate the amounts from them). Bottom line, the MySQL cluster COULD be sufficient for Amos's needs, but further data must be gathered before a decision could be made. > -----Original Message----- > From: Cyril SCETBON [mailto:[EMAIL PROTECTED] > Sent: Tuesday, November 20, 2007 12:13 PM > To: Imri Zvik > Cc: Yonah Russ; [email protected] > Subject: Re: MySQL Cluster for HA? What about PostgresQL PGCluster? > > > > Imri Zvik wrote: > > Hi, > > > > The MySQL cluster can run perfectly on one physical node. > > > > The 3 nodes you're referring to are at least 1 management node, and > at > > least 1 API ("mysqld") node, and at least 1 data/storage ("ndbd") > node. > > They can all reside on the same physical node. > yeah, but you lose the high availability if the host crashes. > > > > The main issue with NDB version 5.0 (from my point of view) is that > it > > must load all data into memory at runtime, so if your database is > larger > > than your amount of RAM, you better find some other solution, or > split > > it to enough replicas (data nodes) so that each chunk would fit. > > This problem is going to be solved with 5.1, > just for the data blocks cause indexes are still in memory. > but it is not even near > > being production-ready (at least last time I've checked). > yes, but the current version is an RC (release candidate) which > announces a release in the next 2 months. > > > > > >> -----Original Message----- > >> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf > Of > >> Yonah Russ > >> Sent: Tuesday, November 20, 2007 6:53 AM > >> To: Amos Shapira > >> Cc: [email protected] > >> Subject: Re: MySQL Cluster for HA? What about PostgresQL PGCluster? > >> > >> Hi, > >> > >> AFAIK MySQL cluster requires using the NDB engine which is not 100% > >> compatible with MYISAM, etc. The more recent a version you have the > >> better off you will be but there was one point where autoincrement > >> wasn't even supported. Also from what I know, a NDB cluster needs at > >> least three nodes. > >> > >> That doesn't mean you can't have an active-active database. If you > >> application is ready for it, you can set up MySQL in a Master Master > >> configuration (aka multimaster). For your application to be > compatible > >> you basically need to use only autoincrement primary keys for all > your > >> tables but you should read the whole Megilah - here is a good > article: > >> http://www.onlamp.com/pub/a/onlamp/2006/04/20/advanced-mysql- > >> replication.html > >> > >> Google has also released some code for multimaster configurations > and > >> they have some docs also: > >> http://code.google.com/p/mysql-master-master/ > >> > >> Regarding Postgres- I can't recommend anything specific but I am > >> looking into pgpool and pgpool II for a new project. > >> > >> Hope that helps, > >> Yonah > >> > >> > >> On Nov 20, 2007 2:51 AM, Amos Shapira <[EMAIL PROTECTED]> > wrote: > >> > >> > >> Hello, > >> > >> We are looking at enhancing one of our servers, which runs > > CentOS > >> 5 on > >> amd64, for HA using Linux Virtual Servers (LVS). The server runs > >> a web > >> site using MySQL 5.0.22 and of course we'll need to replicate > >> that on > >> the second server as well. > >> > >> Is MySQL Cluster the right solution for us? > >> > >> At least for now, we think we can do with a master-slave > > solution > >> (i.e. only one server serving while the other is in "hot > >> standby"), > >> but if it's possible to take advantage of both servers at the > >> same > >> time and double our capacity then it would be very useful too. > >> > >> I also have a small web service using PostgresQL (8.1.9, from > >> CentOS > >> packages) on the same server which will also have to be > >> replicated. > >> What do people usually use to do this? Is PGCluster a practical > >> option? > >> > >> Thanks, > >> > >> --Amos > >> > >> > > ================================================================= > >> To unsubscribe, send mail to [EMAIL PROTECTED] > >> <mailto:[EMAIL PROTECTED]> with > >> the word "unsubscribe" in the message body, e.g., run the > > command > >> echo unsubscribe | mail [EMAIL PROTECTED] > >> > >> > >> > > > > =============================================================== > > To unsubscribe, send mail to [EMAIL PROTECTED] with > > the word "unsubscribe" in the message body, e.g., run the command > > echo unsubscribe | mail [EMAIL PROTECTED] > > > > > > ================================================================To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
