I'm not an expert on this, but it seems to me that having some way to do this replacement (512n -> 512e) would be OK, though the performance impact may be considerable so we might want a warning message, or to require a force flag?
--matt On Wed, Oct 31, 2018 at 3:03 PM Mike Zeller <[email protected]> wrote: > When attempting to replace a drive in an existing 512 byte zpool with a > 512e > drive, zfs will complain with a message similar to: > > cannot replace c4t0d0 with c5t0d0: devices have different sector alignment > > ZFS is attempting to use the physical block size (4096 bytes) rather than > the > logical block size (512 bytes). This causes operators some pain when you > have > an existing 512 byte pool on AF disks. > > Do others find it reasonable to allow ZFS to match on either the physical > or > logical block size of the new device? I have been testing a patch > originally > written by Joshua Clulow at Joyent which can be viewed at > https://cr.joyent.us/4997. I have tested the patch on a recent illumos > platform > (in this case SmartOS) and I was successfully able to replace a drive in a > 512 > byte pool with a 512e drive. More of the testing notes can be seen in > https://smartos.org/bugview/OS-4718. > > Currently the OS will output warnings on the console about the disk having > a > block alignment that is larger than the pool's alignment when doing the > replace > and when importing the pool. There are likely some performance impacts when > adding a drive of this type to an existing pool that I have not dug into at > all. However, I am willing to drive this patch forward, so I am looking > for > some initial feedback on what has been done so far. > > Thanks, > Mike > > *openzfs <https://openzfs.topicbox.com/latest>* / openzfs-developer / see > discussions <https://openzfs.topicbox.com/groups/developer> + participants > <https://openzfs.topicbox.com/groups/developer/members> + delivery options > <https://openzfs.topicbox.com/groups/developer/subscription> Permalink > <https://openzfs.topicbox.com/groups/developer/T85845c743b75a578-M14778595301cae6a864b4e04> > ------------------------------------------ openzfs: openzfs-developer Permalink: https://openzfs.topicbox.com/groups/developer/T85845c743b75a578-Ma5731e10c7bc33d544c9fac3 Delivery options: https://openzfs.topicbox.com/groups/developer/subscription
