docs: formatdomain: Document disk serial truncation status quo

Disk serials are truncated arbitrarily and silently by qemu depending on
the device type and how they are configured. Since changing the current
state would lead to more regressions than we have now, document that the
truncation is arbitrary.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
This commit is contained in:
Peter Krempa 2021-06-04 14:08:40 +02:00
parent e30584ff06
commit 2c8b341af8

View File

@ -3146,6 +3146,16 @@ paravirtualized driver is specified via the ``disk`` element.
may look like ``<serial>WD-WMAP9A966149</serial>``. Not supported for
scsi-block devices, that is those using disk ``type`` 'block' using
``device`` 'lun' on ``bus`` 'scsi'. :since:`Since 0.7.1`
Note that depending on hypervisor and device type the serial number may be
truncated silently. IDE/SATA devices are commonly limited to 20 characters.
SCSI devices depending on hypervisor version are limited to 20, 36 or 247
characters.
Hypervisors may also start rejecting overly long serials instead of
truncating them in the future so it's advised to avoid the implicit
truncation by testing the desired serial length range with the desired device
and hypervisor combination.
``wwn``
If present, this element specifies the WWN (World Wide Name) of a virtual
hard disk or CD-ROM drive. It must be composed of 16 hexadecimal digits.