> On Dec 4, 2018, at 2:47 PM, Matthew Ahrens <[email protected]> wrote: > > 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?
IIRC, that was the original intent when George first described it. -- richard > > --matt > > On Wed, Oct 31, 2018 at 3:03 PM Mike Zeller <[email protected] > <mailto:[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 <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 <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-Ma5731e10c7bc33d544c9fac3> ------------------------------------------ openzfs: openzfs-developer Permalink: https://openzfs.topicbox.com/groups/developer/T85845c743b75a578-M021c379e84aa30ef91474e56 Delivery options: https://openzfs.topicbox.com/groups/developer/subscription
