It's been a while since I've given a look at this and I've been (blindly) following my build recipe for awhile now so I am wondering lately:
when I create a zpool or when adding a subsequent vdev I always:
And this is fine and it works and I get my intended ashift=12
However, this is annoying and inconvenient especially since it requires taking the zpool offline to delete the nop device.
I wonder:
1. if my drives being truly 4k, or with the use of:
vfs.zfs.min_auto_ashift: 12
when all is said and done and zdb reports ashift=12, even when I didn't use the nop hack nor adjust vfs.zfs.min_auto_ashift, is that all I care about? Stated another way, is the nop hack doing something else I'm not aware of that I'd be losing if I didn't do it and only looked at the ashift outcome?
2. once a zpool is created and the ashift is established, will that ashift be inherited by subsequent vdevs such that I could never check zdb ever again for that zpool and it will always read the same ashift=12, even after adding several more vdevs comprised of different drive sizes?
3. assuming I still wanted to do the nop hack for vdev additions ... to avoid having to take the zpool offline to delete the nop is there any reason I can't leave it there while the zpool is in use until I can conveniently remove it at the next reboot (weeks or months away)? i.e. is there any conceivable way that removing it could result in data loss?
when I create a zpool or when adding a subsequent vdev I always:
gnop create -S 4096 /dev/da24
zpool add data1 raidz3 da24.nop da{25,26,27,28,29,30,31,32,33,34,35}
zpool export data1
gnop destroy /dev/da24.nop
zpool import data1
And this is fine and it works and I get my intended ashift=12
However, this is annoying and inconvenient especially since it requires taking the zpool offline to delete the nop device.
I wonder:
1. if my drives being truly 4k, or with the use of:
vfs.zfs.min_auto_ashift: 12
when all is said and done and zdb reports ashift=12, even when I didn't use the nop hack nor adjust vfs.zfs.min_auto_ashift, is that all I care about? Stated another way, is the nop hack doing something else I'm not aware of that I'd be losing if I didn't do it and only looked at the ashift outcome?
2. once a zpool is created and the ashift is established, will that ashift be inherited by subsequent vdevs such that I could never check zdb ever again for that zpool and it will always read the same ashift=12, even after adding several more vdevs comprised of different drive sizes?
3. assuming I still wanted to do the nop hack for vdev additions ... to avoid having to take the zpool offline to delete the nop is there any reason I can't leave it there while the zpool is in use until I can conveniently remove it at the next reboot (weeks or months away)? i.e. is there any conceivable way that removing it could result in data loss?