On Wed, 2003-07-09 at 21:21, Bruce Dawson wrote: > On Wed, 2003-07-09 at 14:37, Robert Anderson wrote: > > ... > > I'm still open for problems to work on. If you have something you've > > been trying to do and would like to have the groups input, please send > > an email or be ready to explain your problem to the group on Monday. > >... > > Well, something I've been struggling with lately is how to plan a site > for upgrading with minimal downtime (i.e. just the time required to > reboot). > > One thing that we've looked at is having two computers with identical > configurations - software and hardware, and use LVS (or some equivalent) > to switch the web and mail services to the other system when one goes > down. However, this falls apart rather quickly - databases need to be > duplicated, resync-ing things like log files are a royal pain, ... > > I'm mostly wondering how other sites handle this with minimal hardware > and proprietary software investments. > > --Bruce
The amount of downtime you'll have is proportional to the amount of money you spend. I'm sure you realize this and were just hoping to get around it somehow. The upgrade operation is rather complex. As you point out things can get sticky. My experience is that the time needed to synchronize databases can be minimized but not completely avoided. Much of the rest of the system can be duplicated in advance. If you roll your logs as part of taking the primary system offline then you can simply copy the old versions to the new system. It is then no different than a normal log rolling operation. The DB resync time I've minimized in the past by using a full DB backup from earlier in the day to populate the standby DB and then updating it with only the newer data from the DB at the time of switchover. This often results in a downtime measured in minutes rather than an hour or more. The specific methods to use for this will of course depend on the database being used. -- Dan Coutu Managing Director Snowy Owl Internet Consulting, LLC http://www.snowy-owl.com/ _______________________________________________ gnhlug-discuss mailing list [EMAIL PROTECTED] http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss