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: openzfs-developer Permalink: https://openzfs.topicbox.com/groups/developer/T85845c743b75a578-M14778595301cae6a864b4e04 Delivery options: https://openzfs.topicbox.com/groups/developer/subscription
