Should swap space be mirrored via geom?

Peter Steele psteele at maxiscale.com
Wed Jan 14 08:04:44 PST 2009


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?

 



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