On Mon, Nov 7, 2011 at 3:51 PM, Zhu Han <schumi.han@xxxxxxxxx> wrote: > > > > On Mon, Nov 7, 2011 at 10:44 PM, Martin Rusko <martin.rusko@xxxxxxxxx> > wrote: >> >> On Mon, Nov 7, 2011 at 3:12 AM, Zhu Han <schumi.han@xxxxxxxxx> wrote: >> > Hi, >> > >> > I got several advanced format disk, whose physical size is 4096 bytes, >> > but >> > its logical size is 512 bytes: >> > $ sudo fdisk -l /dev/sdb >> > >> > Disk /dev/sdb: 750.2 GB, 750156374016 bytes >> > 255 heads, 63 sectors/track, 91201 cylinders >> > Units = cylinders of 16065 * 512 = 8225280 bytes >> > Sector size (logical/physical): 512 bytes / 4096 bytes >> > I/O size (minimum/optimal): 4096 bytes / 4096 bytes >> > Disk identifier: 0x00000000 >> > >> > Disk /dev/sdb doesn't contain a valid partition table >> > >> > Is there any special tuning knob I should notice before formating it? >> > IMHO, >> > set the sector size as 4096 bytes is enough. The default block size is >> > 4096 >> > bytes. >> > $ sudo xfs_info /dev/sdb >> > meta-data=/dev/sdb isize=256 agcount=4, agsize=45785912 blks >> > = sectsz=4096 attr=2 >> > data = bsize=4096 blocks=183143646, >> > imaxpct=25 >> > = sunit=0 swidth=0 blks >> > naming = version 2 bsize=4096 >> > ascii-ci=0 >> > log =internal bsize=4096 blocks=89425, >> > version=2 >> > = sectsz=4096 sunit=1 blks, >> > lazy-count=1 >> > realtime =none extsz=4096 blocks=0, rtextents=0 >> > >> > >> >> One thing is to make sure, that your partitions are aligned to >> physical sector size. Recent fdisk will do it properly. See options >> '-c' (or 'c' in interactive mode) which sets DOS compatibility mode >> and '-u' (or 'u' in interactive mode) which sets units which fdisk >> uses. You want no DOS compatibility and units of sectors. Then first >> partition starts on 2048 sector (so 1MiB is available for GRUB for >> example) and it's gets things nicely aligned ... 2048 logical sectors >> = 256 physical sectors. > > If the whole disk is used for the file system (it is not a bootable disk so > no partition is created), can I ignore these settings safely? > I've heard about some WD drives with jumper switch, which could be used to shift logical sectors by one to be aligned somehow with dos-compatible partitioning. If you don't have this jumper on or you don't have drive with it, you can ignore it. >> >> If you are creating more than one partition, use something like +34G >> while specifying end of the partition (so the next one is aligned as >> well). >> _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
