Re: [PATCH 2/3] Add EVPD page 0x83 to sysfs

Douglas Gilbert
2014-03-07T11:18:28Z

On 14-03-07 12:01 PM, James Bottomley wrote:
> On Fri, 2014-03-07 at 11:51 +0100, Hannes Reinecke wrote:
>> On 03/07/2014 11:39 AM, James Bottomley wrote:
>>> On Thu, 2014-03-06 at 10:01 +0100, Hannes Reinecke wrote:
>>>> So the only 'proper' solution would be to add a bitmap of supported
>>>> pages; however, this would be 256 bits = 32 bytes of additional
>>>> space required for struct sdev.
>>>> Which I'm a bit reluctant do to, as it'll be a sparse array in most
>>>> cases, adding to quite some wasted space.
>>>
>>> Why per sdev? Isn't it per target? The supported EVPD page list
>>> shouldn't really vary for luns of the same target unless something very
>>> strange is happening in the array.
>>>
>> Spec says it's per LUN:
>
> Specs say a lot of "interesting" things. The question is what's common
> practise in the field.

I have a SAS controller (not from a major) that in jbod
mode sends through different physical SAS and SATA disks
as different LUNs in the _same_ target.

Needless to say on a target from that controller there is not
a lot of commonality between its LUN's VPD page sets.

Would it be possible in a sysfs VPD info directory to have
a timestamp (e.g. CLOCK_MONOTONIC) of when the VPD info
was read?

Doug Gilbert