On Fri, 14 Nov 2003, Rob Siemborski wrote: > On Fri, 14 Nov 2003, Simon Matter wrote: > > > IIRC taking a snapshot with LVM/XFS takes just a few seconds. I guess > > everything should continue after the snapshot. What do the cyrus processes > > do if they receive SIGSTOP? Will they stop immediately or will they not > > stop at all? I mean, if a process receives SIGSTOP while it writes to a > > file, will the write finish before the process stops? > > I'm pretty sure if you just stop the processes where they are, you'll > still get an inconsistant store. (E.g. the mail file is written out, but > the index files aren't yet updated).
As I think about this further -- it might be possible to somehow signal to all of the cyrus processes that they need to reach a quiescent state, but I suspect that doing this to the point of absolute consistancy may be significantly time consuming, as you may find yourself waiting for network operations to complete also. I don't think the work to even get to that point is trivial however. -Rob -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Rob Siemborski * Andrew Systems Group * Cyert Hall 207 * 412-268-7456 Research Systems Programmer * /usr/contributed Gatekeeper