Hi, Although this is slightly off topic it is important that Sequoia has at least 512MB of memory. One time we managed to screw up the memory settings for the JVM and revert to the defaults of 64MB. Due to the caching of parsed requests and the caching that is done of intra cluster messages we ran into ugly out of heap mempory errors that would kill one of the threads so the controller would effectively hang.
Dave ________________________________________ From: [EMAIL PROTECTED] [EMAIL PROTECTED] On Behalf Of Robert Hodges [EMAIL PROTECTED] Sent: Thursday, 17 January 2008 11:20 AM To: Sequoia general mailing list Subject: Re: [Sequoia] Recovery Log Hi James, I'm embarrassed to say I have not done much scale testing on memory size because the hosts I normally use have only 1GB. (OK, it's not so bad, because there are several of them, but still...) Your settings are consistent with what many commercial customers use. You are correct about external databases--it means on another host. All things considered I would still move the recovery log off Hypersonic as we have seen a number of problems with it in production situations. Cheers, Robert On 1/16/08 4:19 PM, "Stuart James" <[EMAIL PROTECTED]> wrote: > Hi Robert, > > Under our current load of course we do not see this, as the writes per > second are minimal, we are much more concerned with reads. Also the > Controllers we are using are not as powerful as the backends databases. > >> The backlog should disappear if you switch the log to write to a more >> capable database such as MySQL. MySQL by contrast can perform 2000 >> or more updates per second on a single thread without difficulty. >> You correctly noted, by the way, that there is a single connection. >> We use either MySQL or PostgreSQL in the commercial products based on >> Sequoia. >> >> The recovery log is written asynchronously, so it does not at least in >> theory have too much impact on SQL update rates. However, Hypersonic >> is pretty slow and uses a lot of memory when you have large >> quantities of data. Switching to an external database should speed >> things up at least a bit. > > What amount of memory do you suggest allocating to Sequoia on startup, > currently we are setting 768 and max of 1024, and if we were to > increase this, is their a noticeable performance increase? > > When your refer to external database, do you mean external to the > server that sequoia sits on. > > > Regards, > > Stuart > _______________________________________________ > Sequoia mailing list > Sequoia@lists.forge.continuent.org > https://forge.continuent.org/mailman/listinfo/sequoia -- Robert Hodges, CTO, Continuent, Inc. Email: [EMAIL PROTECTED] Mobile: +1-510-501-3728 Skype: hodgesrm _______________________________________________ Sequoia mailing list Sequoia@lists.forge.continuent.org https://forge.continuent.org/mailman/listinfo/sequoia _______________________________________________ Sequoia mailing list Sequoia@lists.forge.continuent.org https://forge.continuent.org/mailman/listinfo/sequoia
