On Fri, 2014-01-17 at 12:20 -0500, Douglas Gilbert wrote: > Hannes Reinecke and I would like to attend LSF and present > a talk on the new generation copy offload (a.k.a. ODX). > > Most discussions about copy offload at the storage level > are based on T10's 15 year old xcopy(LID1), specifically its > disk->disk copy. This year T10 hopes to standardize a new > generation copy offload whose generic name is xcopy(LID4). > A subset of xcopy(LID4) that does disk->disk copies and > already has vendors with products supporting it, has the > market name of ODX. > > ODX is ROD (Representation Of Data) based (as is > xcopy(LID4)) where the copy is split into two steps: > disk->held [SCSI POPULATE TOKEN command] > held->disk [SCSI WRITE USING TOKEN command] > > We would like to discuss how the interfaces (both to the > block layer and the filesystem) should look like for > implementing ROD based copies. > Further we would like to discuss if and how the Linux > target subsystem can be expanded to support ODX in the > future, in addition to the already existing support for > xcopy(LID1). > > An example of one of the new ODX/xcopy(LID4) capabilities > can be found in this post: > http://www.spinics.net/lists/linux-scsi/msg71411.html > > We hope to be able to demonstrate some low level Linux > utilities doing ODX copies on a remote array. > +1. I've looked briefly at how an initial implementation might work target side, and while the SCSI pieces are straight-forward enough to implement, the bigger issue is how an interface for snapshots within the backend might work to satisfy the requirements for POPULATE TOKEN.. --nab -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
