[ZFS] Booting from zpool created on 4k-sector drive

Emil Smolenski am at raisa.eu.org
Mon Feb 28 22:18:04 UTC 2011

On Sun, 27 Feb 2011 20:57:14 +0100, James R. Van Artsdalen
<james-freebsd-fs2 at jrv.org> wrote:

> Emil Smolenski wrote:
>> Hello,
>> There is a hack to force zpool creation with minimum sector size equal
>> to 4k:
>> # gnop create -S 4096 ${DEV0}
>> # zpool create tank ${DEV0}.nop
>> # zpool export tank
>> # gnop destroy ${DEV0}.nop
>> # zpool import tank
>> This change is permanent. The only possibility to change the value of
>> ashift is: zpool destroy/create and restoring pool from backup.
> Is ashift a property of the pool or a property of the device?

It is property of the ZFS pool. It is calculated when the pool is created
based on the sector size advertised by devices.

> I'm wonder about the disk replacement scenario, where the replacement
> disk cannot be smaller than the disk it replaces.

And the new disk must advertise sector size equal or smaller than
2**ashift of the existing pool.


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