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A brief introduction to ZFS (disk) GUIDs
Although ZFS commands like '
ZFS likes identifying pool-related objects with what it calls a 'GUID',
a random and theoretically unique 64-bit identifier. Pools have GUIDs,
vdevs have GUIDs, and, specifically, disks (in pool configurations) have
GUIDs. ZFS internally uses the GUID for most operations; for instance,
almost all of the kernel interfaces that
(The 'numeric identifier' that you can use to have '
In a pool's configuration, entries for disks have a bunch of information
to help ZFS identify the right device: the GUID of the disk, the device
it's expected to be found on, and the physical path and device ID of
that device. You can see most of a pool's raw configuration, complete
with this information about each disk, with '
As you might guess, disks being used by ZFS have an on-disk label (in
fact they have four copies of it, two at the start of the ZFS slice and
two at the end). Among other things, this disk label has the disk's
GUID. You can dump a disk's ZFS label with '
(On disks that are part of a live vdev, the disk label also has a copy of the vdev's information; on spare disks, all the label has is the disk's GUID, the version, and the state.)
(I'm not entirely clear where the full pool configuration is stored;
it's in the pool somewhere, but it's unfortunately not in the disk
labels, so it's not trivial to dump it with
Note that ZFS GUIDs are not real GUIDs. Real GUIDs are 128-bit objects and are conventionally printed in a special format; ZFS GUIDs are only 64-bit ones and are conventionally printed as plain decimal numbers.
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