Re: thin provisioned LUN support

Martin K. Petersen
2008-11-07T19:55:06Z

>>>>> "Ted" == Theodore Tso <tytso@mit.edu> writes:

Ted> I thought ATA didn't have any TRIM alignment requirements, and
Ted> it's T10 that wants to add it to the SCSI side?

The current UNMAP proposal in SCSI doesn't have requirements either.

Array vendors, suddenly realizing all the work they have to do to
support this, are now talking about imposing additional constraints
(orthogonal to the UNMAP command set) because of limitations in their
existing firmware architectures.

It obviously much easier for the array vendors to export a Somebody
Elses Problem VPD page containing a constant than it is to fix
inherent limitations in their internal architecture.

We're trying to point out that that's an unacceptable cop out for
something that's clearly their problem to deal with.

My concern is that if we start doing the array people's homework at
the OS level they won't be inclined to fix their broken firmware
design. Ever.

--
Martin K. Petersen Oracle Linux Engineering