See Comments Inline: Greg
On Fri, Oct 26, 2001 at 12:13:21PM +0200, Klaus Jaehne wrote: > > On Tue, 23 Oct 2001, Greg Hewett wrote: > > My experience has been that cyrus fails over pretty clean. Depending > > on the number of users, it might not make sense to reconstuct the > > databases at a time of fail over. > > OK, thanks for the information - I've got some more questions: > - "fails over pretty clean": Did you have any trouble with failover yet? Well, the reason that I say pretty clean is because I have not failed over a box of 15,000 users on 2.0.x. I am still in the lab with this concept. We do have a deployment of 1.6.x with 20,000 users (two instances in a four node cluster) that does not deal with corrupt databases, and it has only had 9 minutes of downtime in the last three years. I am not sure how many hard failovers that consisted of. In short, I have not experienced any problems, but I cannot guarentee that it will not happen. My advice is to make sure that you have a place to test the solution. Even if it is one machine, load it up with data, and start turning it off and back on over and over and over. ;) > - What failover software do you use? Veritas Cluster Server 1.3.0. It is probably the easiest solution. It is definately not the cheapest. > - Could it happen that DB3 files (like /var/imap/mailboxes.db) get > destroyed when a server crashes and these files are open for writing? I am sure they can, but I am not familiar enough with the details of sleepcat db to answer this question definativly. With HA Solutions, I think that you have to balance the costs of downtime versus the time that you take to do the paranoid checks of the database. I would like to investigate more on how different corrupts affect users. <OT> Some applications do not fit well into the HA arena. I am dealing with an app right now, that will consistantly get a corrupt database, and it can take up to 10 minutes with 7 users to rebuild and fix the databases. IMHO, that is unacceptable. This application is going through some changes, so I hope they get it right on the next version. I do believe that cyrus does fit very well in the HA arena. </OT> > > btw: What about a "redundant-Cyrus-server-setup-HOWTO"? That would be a great idea. I will see what I can contribute. > > -- > geetings, > Klaus J?hne > ________________________________________________________________________ > Thinking Objects Software GmbH, Lilienthalstr. 2, 70825 Stuttgart, DE > phone 49 711 88770 400, fax 449, [EMAIL PROTECTED], http://www.to.com/ > ======================================================================== > Linux without limits: http://linux.s390.org/ > ------------------------------------------------------------------------ >
