Should swap space be mirrored via geom?
We have systems setup using geom based mirroring where the drives are partitioned into three slices, one for the OS, one for the swap partition, and one for our application data. We have four hot-swappable SATA drives per system. At present we only have the OS slice mirrored with geom, and our own data partition is definitely not a candidate for mirroring. The swap slice is not mirrored, so we end up with 4x4GB of space on each system (which is probably way more than we need). We have been debating whether or we should mirror the swap partitions as well. I set it up not mirrored based on some articles I read on the net, but we're concerned what might happen to a system if a drive died at a time when the its swap partition contained active pages. My first reaction would be that the applications bound to these pages would crash, something that would not happen if we used swap mirroring. Can anyone shed some light on this? ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Should swap space be mirrored via geom?
On Jan 14, 2009, at 8:04 AM, Peter Steele wrote: We have been debating whether or we should mirror the swap partitions as well. I set it up not mirrored based on some articles I read on the net, but we're concerned what might happen to a system if a drive died at a time when the its swap partition contained active pages. My first reaction would be that the applications bound to these pages would crash, something that would not happen if we used swap mirroring. If you don't mirror swap space, and a drive goes out, you're almost certain to experience a kernel panic and not just application failures in userland. Unless you have an urgent need for lots of swap space available, it's much better from the standpoint of system reliability to mirror swap also. Regards, -- -Chuck ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
RE: Should swap space be mirrored via geom?
If you don't mirror swap space, and a drive goes out, you're almost certain to experience a kernel panic and not just application failures in userland. Unless you have an urgent need for lots of swap space available, it's much better from the standpoint of system reliability to mirror swap also. That's what we assumed might be the danger. It's pretty obvious when you think about it ultimately and I'm curious why anyone would have suggested not to mirror the swap partition. Thanks for the reply. Peter ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
