Mehdi Sarmadi wrote:
Hi Thanks Robert, I've read that. I'm just wondering what model does RH Cluster Suite uses for clustering MySQL. I know much about MySQL Cluster & Replication. I'm looking for cluster suites e.g. Redhat or Sun. I wonder how cluster suite cope with - known replication problems and - cluster unawareness of MySQL engine and - shared-nothing policy that mysql does. I heard of something here: http://www.redhat.com/archives/linux-cluster/2006-June/msg00158.html Afterall, I look for what Redhat proposes and recommend for HA/Failover and Clustering for MySQL. Looking fwd to your reply Best Regards
Hi Medhi, I'm not sure what you mean by "what model" RH Cluster Suite uses. I don't know the answers to MySQL-specific questions regarding known replication problems, cluster unawareness and share-policy. I also can't speak for what "Red Hat Recommends" but I can perhaps tell you what I know about the topic: - Cluster Suite is able to do High Availability (HA) MySQL with active/passive MySQL. That is, have a single MySQL server in a cluster, and if that server goes down, another node in the cluster takes over its MySQL server duties. No problem. - To accomplish this, I recommend using GFS file system on shared storage, because then updates made to the MySQL data will be seamlessly seen by the other nodes that are standing by (passive). - If you don't use GFS and shared storage, then you might be able to have multiple MySQL servers running simultaneously on their own copies of the database (Active/Active). Then, of course, you run into problems of how to replicate the data properly, which is what you were probably talking about with replication problems and share policy. I'm sorry, but I can't help you there. If you could solve those replication issues, you could then use something like LVS / Piranha to do load balancing of the MySQL requests. - Since normal MySQL isn't cluster-aware, I think database updates from multiple servers (Active/Active) over GFS are likely to cause database corruption unless you're using the "MySQL Cluster" product which I don't know much about. - Other people on this list have talked about getting multiple MySQL servers (Active/Active) to work cooperatively over GFS without corruption as long as they're not updating records. In other words, just for read-only queries. I'm not sure what kinds of things they need to get this to work properly. There was a thread in October in linux-cluster under the subject "Multiple Active MySQL instances", but I don't remember what all was said. I do remember them saying that it only works with MyISAM tables. I recommend reading the archives, at this link: http://www.redhat.com/archives/linux-cluster/ If they have gotten this working, then again, you could use LVS to do load balancing if you want. I hope this helps. Regards, Bob Peterson Red Hat Cluster Suite -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
