13.08.2010 14:27, Stan Hoeppner wrote: > Michael Tokarev put forth on 8/13/2010 1:24 AM: > >> So the question that remains is: why? > > 4096 is the default block size and has been since at least 2.6.26 when I > started using XFS. From "man mkfs.xfs": > > OPTIONS > -b block_size_options This is block size. But XFS_IOC_DIOINFO returns _sector_ size. All other XFS filesystems we have are made with the same 4096 _block_ size. > [..] The default value is 4096 bytes (4 KiB) > >> So why xfs decided the block size is 4K?? That was the wrong question. The right one is about _sector_ size, not _block_ size. The filesystem in question has _sector_ size =4096, all the rest has it =512. >> And a related question, -- is there a way to create >> xfs fs with the right sector size? > > Yes. > > -s sector_size > This option specifies the fundamental sector size of the filesystem. The > sector_size is specified either as a value in bytes with size=value or as a > base two logarithm value with log=value. The default sector_size is 512 Yeah, the default is 512, my manpage agrees. But yet I've a filesystem that has it =4096... But maybe it were specified during filesystem creation. I re-read the mkfs.xfs manpage yesterday, but somehow missed the sector size option (!), which you quoted above. Maybe we used it year ago when creating the filesystem, for yet to be determined reason... ;) I just tried to create an xfs filesystem on this machine (on a small reserved partition) - it uses sector size = 512 as expected. >> By the way, how one can check the "sector size" of a >> block device nowadays? > > cat /sys/block/[device]/queue/hw_sector_size And it shows 512 even for the md array in question. > That will give you the hardware sector size. As mentioned above, the XFS > sector size can be manually specified during FS creation. Thus they may not > match, which is likely the case with the 600GB FS you're having the problems with. Yup! Thank you all for the information, and please excuse me for the noize - just too many stuff at once... ;) /mjt _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
