SUMMARY: graceful removeal of swap

From: FXCM - <>
Date: Wed Oct 12 2005 - 17:29:57 EDT
Hi All,

Thanks for all the responses. 

Large majority of people stated that swap -d does as graceful an exit
as possible - if any pages can't be moved to memory or another swap
partition it will fail. Several people suggested making a temporary file
swap if no other swap device exists (which in my case it wouldn't).
Borrowed from Daryl Mitchell's response:

mkfile <size> <filename>
swap -a <filename>

swap -d <original swap>
rebuild swap slice under disksuite/md
swap -a <new md swap)

amend vfstab

This is indeed what I ended up doing, as I didn't want to rely
exclusively on memory, although I probably could have, but one can never
be too safe, and the work required is minimal. 

Also, a few people asked why on earth I would want to mirror swap. Good
question, and our original position had been not to mirror, but that was
wrong for 2 very important reasons:

1 - hot swapping after complete disk failure
2 - crash dumps after complete disk failure

1 is impossible without a reboot if the disk that failed contains the
swap partition - it can't be deleted because of I/O errors, so the disk
itself can't be nicely removed from the OS, at least to my knowledge. 2
dump will obviously be unable to generate, unless of course the drive is
replaced before the first boot after the crash, but those chances are

Below is my original question - thanks again for the help - has worked
like a charm so far.

We have several Solaris 8 systems running DiskSuite that do not have
swap partitions, and would like to change them to be mirrored in case
complete disk failure. If possible, it would be nice to change them

 My concern is that a simple swap -d will abrubtly remove swap and all
existing pages may be lost, which would not be nice for our production
applications. Is there a more graceful way of removing existing swap,
the swap -d command take care of that?
sunmanagers mailing list
Received on Wed Oct 12 17:30:25 2005

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