Darren J Moffat wrote: > As part of the ARC inception review for ZFS crypto we were asked to > follow up on PSARC/2006/370 which indicates that swap & dump will be > done using a means other than a ZVOL. > > Currently I have the ZFS crypto project allowing for ephemeral keys to > support using a ZVOL as a swap device. > > Since it seems that we won't be swapping on ZVOLS I need to find out > more how we will be providing swap and dump space in a root pool. > The current plan is to provide what we're calling (for lack of a better term. I'm open to suggestions.) a "pseudo-zvol". It's preallocated space within the pool, logically concatenated by a driver to appear like a disk or a slice. It's meant to be a low overhead way to emulate a slice within a pool. So no COW or related zfs features are provided, except for the ability to change its size without having to re-partition a disk. A pseudo-zvol will support both swap and dump.
It will also be possible to use a slice for swapping, just as is done now with ufs roots. But we're hoping that the overhead of a pseudo-zvol will be low enough that administrators will take advantage of it to simplify installation (it allows a user to dedicate an entire disk to a root pool, without having to carve out part of it for swapping.) Eventually, swapping on true zvols might be supported (the problems with swapping to zvols are considered bugs), but fixing those bugs are a bigger task than we want to take on for the zfs-boot project. We decided on pseudo-zvols as a lower-risk approach for the time being. > I suspect that the best answer to encrypted swap is that we do it > independently of which filesystem/device is being used as the swap > device - ie do it inside the VM system. > ' > Treat a pseudo-zvol like you would a slice. Lori _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
