svn commit: r300207 - in head: sbin/camcontrol sys/cam/ata sys/cam/scsi sys/dev/ahci sys/geom sys/geom/eli sys/kern sys/sys usr.sbin usr.sbin/diskinfo usr.sbin/zonectl

[Kenneth D. Merry]

On Thu, May 19, 2016 at 15:30:37 +0100, Bruce Simpson wrote:
> Right On Commander!
> 
> Now here is hoping the random-write issues with OpenZFS are solved...

Well, this is of course only the underlying infrastructure for SMR drives.

As for the random write issues with ZFS (or rather sequential I/O going out
in random order), we (Spectra) are working on that in general.

The original plan was to do full SMR support for ZFS, but it looks like we
may get good enough write performance with Drive Managed drives by just
making writes from ZFS to drives more sequential rather than going for full
Host Aware and Host Managed support.  If that turns out that performance
isn't good enough after all, then we'll have to put in the effort to put
Host Aware support at least into ZFS.

That's why I said (in the commit message) that I don't know of anyone
working on using the SMR infrastructure for UFS or ZFS.  Now that the
plumbing is in place in CAM and GEOM, it is possible at the filesystem
level if someone wants to do the work.

Ken
-- 
Kenneth Merry
ken at FreeBSD.ORG