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: # blockdev --getpbsz --getiomin --getioopt --getbsz /dev/mapper/test-scratch 512 512 0 4096 Brian > -- > Stan > > > _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
