[systemd-devel] Proposal: Add Drive Enclosure/Slot mapping to systemd

Tom Gundersen teg at jklm.no
Mon Mar 2 11:24:00 PST 2015

On Mon, Mar 2, 2015 at 5:42 PM, Jordan Hargrave <jharg93 at gmail.com> wrote:
> On Mon, Mar 2, 2015 at 10:24 AM, Andrei Borzenkov <arvidjaar at gmail.com>
> wrote:
>> В Mon, 2 Mar 2015 09:48:51 -0600
>> Jordan Hargrave <jharg93 at gmail.com> пишет:
>> > It would be nice if systemd could discover and display enclosure/bay
>> > slot
>> > mappings for drives in the system.  The /dev/disk/by-path method doesn't
>> > quite work, for SAS drives the ID can change on hotplug.  The slot
>> > mapping
>> > also doesn't handle PCIe SSD devices as they are bare block devices and
>> > don't use SCSI midlayer.  Proposing to add support for something like
>> > /dev/disk/by-enclosure/encl-XXX-slot-YYY symlink for block devices.
>> How it should be discovered? Is there universal method that can be used
>> on majority of systems?
> For Dell system PCIE SSD it requires using ipmitool OEM command to get the
> correct Bus:Device:Function to Enclosure:Slot mapping.  For devices using
> SAS controllers it's a bit more tricky.  There is a sysfs variable for
> enclosure/slot in sysfs for SAS devices with >8 drives on our servers.  The
> driver for some reason doesn't export this info for Dell systems with < 8
> drives.
> Ideally there should be an enclosure.c device defined for every device type.
> Currently only ses.c seems to use this, but SCSI enclosure services aren't
> available on SSDs.

Sounds like something the kernel could/should expose in some uniform way, no?

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