John Cecere wrote: > The man page for dumpadm says this: > > A given ZFS volume cannot be configured for both the swap area and the dump > device. > > And indeed when I try to use a zvol as both, I get: > > zvol cannot be used as a swap device and a dump device > > My question is, why not ?
Swap is a normal ZVOL and subject to COW, checksum, compression (and coming soon encryption). Dump ZVOLs are preallocated contiguous space that are written to directly by the ldi_dump routines, they aren't written to by normal ZIO transactions, they aren't checksum'd - the compression is done by the dump layer not by ZFS. This is needed because when we are writing a crash dump we want as little as possible in IO the stack. -- Darren J Moffat _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
