On 3/2/23 19:26, Bart Van Assche wrote:
On 3/1/23 18:03, Damien Le Moal wrote:
But that is the issue: zones in the middle of each domain can be
activated/deactivated dynamically using zone activate command. So
there is
always the possibility of ending up with a swiss cheese lun, full of
hole of
unusable LBAs because the other domains (other LUN) activated some
zones which
deactivate the equivalent zone(s) in the other domain.
With your idea, the 2 luns would not be independent as they both would
be using
LBAs are mapped against a single set of physical blocks. Zone activate
command
allows controlling which domains has the mapping active. So activating
a zone in
one domains results in the zone[s] using the same mapping in the other
domain to
be deactivated.
Hi Damien,
Your reply made me realize that I should have provided more information.
What I'm proposing is the following:
* Do not use any of the domains & realms features from ZBC-2.
* Do not make any zones visible to the host before configuration of the
logical units has finished. Only make the logical units visible to the
host after configuration of the logical units has finished. Do not
support reconfiguration of the logical units while these are in use by
the host.
* Only support active zones. Do not support inactive zones.
* Introduce a new mechanism for configuring the logical units.
This is not a new idea. The approach described above is already
supported since considerable time by UFS devices. The provisioning
mechanism supported by UFS devices is defined in the UFS standard and is
not based on SCSI commands.
That really cries out for a device-mapper target.
Providing several LUNs only make sense if the hardware supports it;
we've learned that lesson when developing support for Multi-actuator
HDDs. If you want to have several logical disks without hardware support
for it device-mapper is the way to go.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer
