On Thu, Oct 30, 2014 at 02:15:16PM -0500, Stan Hoeppner wrote: > On 10/30/2014 06:46 AM, Brian Foster wrote: > > On Wed, Oct 29, 2014 at 04:38:22PM -0500, Stan Hoeppner wrote: > >> On 10/29/2014 01:47 PM, Eric Sandeen wrote: > >>> On 10/29/14 1:37 PM, Brian Foster wrote: > >>>> On Tue, Oct 28, 2014 at 12:35:29PM -0500, Eric Sandeen wrote: > >>>>> Today, this geometry: > >>>>> > >>>>> # modprobe scsi_debug opt_blks=2048 dev_size_mb=2048 > >>>>> # blockdev --getpbsz --getss --getiomin --getioopt /dev/sdd > >>>>> 512 > >>>>> 512 > >>>>> 512 > >>>>> 1048576 > >>>>> > >>>>> will result in a warning at mkfs time, like this: > >>>>> > >>>>> # mkfs.xfs -f -d su=64k,sw=12 -l su=64k /dev/sdd > >>>>> mkfs.xfs: Specified data stripe width 1536 is not the same as the volume stripe width 2048 > >>>>> > >>>>> because our geometry discovery thinks it looks like a > >>>>> valid striping setup which the commandline is overriding. > >>>>> However, a stripe unit of 512 really isn't indicative of > >>>>> a proper stripe geometry. > >>>>> > >>>> > >>>> So the assumption is that the storage reports a non-physical block size > >>>> for minimum and optimal I/O sizes for geometry detection. There was a > >>>> real world scenario of this, right? Any idea of the configuration > >>>> details (e.g., raid layout) that resulted in an increased optimal I/O > >>>> size but not minimum I/O size? > >>> > >>> Stan? :) > >> > >> Yeah, it was pretty much what you pasted sans the log su, and it was a > >> device-mapper device: > >> > >> # mkfs.xfs -d su=64k,sw=12 /dev/dm-0 > >> > > > > What kind of device is dm-0? I use linear devices regularly and I don't > > see any special optimal I/O size reported: > > It's a dm-multipath device. I pasted details up thread. Here, again: > Oh, I see. So this is just getting passed up from the lower level scsi devices. On a quick look, this data appears to come from the device via the "block limits VPD." Apparently that should be accessible via something like this (0xb0 from sd_read_block_limits()): # sg_inq --page=0xb0 /dev/sdx ... but I don't have a device around that likes that command. It would be interesting to know what makes the underlying device set optimal I/O size as such, but that's just curiosity at this point. :) Brian > # multipath -ll > 3600c0ff0003630917954075401000000 dm-0 Tek,DH6554 > size=44T features='0' hwhandler='0' wp=rw > |-+- policy='round-robin 0' prio=50 status=active > | `- 9:0:0:3 sdj 8:144 active ready running > `-+- policy='round-robin 0' prio=10 status=enabled > `- 1:0:0:3 sdf 8:80 active ready running > > > # blockdev --getpbsz --getss --getiomin --getioopt /dev/dm-0 > 512 > 512 > 512 > 1048576 > > # blockdev --getpbsz --getss --getiomin --getioopt /dev/sdj > 512 > 512 > 512 > 1048576 > > # blockdev --getpbsz --getss --getiomin --getioopt /dev/sdf > 512 > 512 > 512 > 1048576 > > > > Cheers, > Stan > _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
