--- src/sbin/disklabel/disklabel.8 2008/07/10 03:15:56 1.22 +++ src/sbin/disklabel/disklabel.8 2008/08/04 20:31:36 1.22.2.1 @@ -36,7 +36,7 @@ .\" $FreeBSD: src/sbin/disklabel/disklabel.8,v 1.15.2.22 2003/04/17 17:56:34 trhodes Exp $ .\" $DragonFly$ .\" -.Dd July 10, 2008 +.Dd July 27, 2008 .Dt DISKLABEL 8 .Os .Sh NAME @@ -133,13 +133,26 @@ All .Nm forms require a disk device name, which should always be the raw device name representing the disk or slice. -For example -.Pa da0s0 +.Dx +uses the following scheme for slice numbering: +If the disk doesn't use +.Xr gpt 8 , +but e.g. MBR (typically laid out by +.Xr fdisk 8 ) , +then slice 0, e.g. +.Pa da0s0 , represents the entire disk regardless of any DOS partitioning, this is called the compatibility slice, -and -.Pa da0s1 -represents a BSD slice. +and slice 1 and onward, e.g. +.Pa da0s1 , +represents a +.Bx +slice. +If the disk does use GPT (typically laid out by +.Xr gpt 8 ) , +then all slices are +.Bx +slices, slice 0 isn't special, it is just the first slice on the disk. You do not have to include the .Pa /dev/ path prefix when specifying the device. @@ -393,7 +406,9 @@ intend to create a .Dq dangerously-dedicated disk, such as .Ar da0s0 . -This command is typically run on a BSD slice such as +This command is typically run on a +.Bx +slice such as .Ar da0s1 . .Pp .Nm @@ -414,7 +429,9 @@ In addition to writing a new volume labe If run on the compatibility slice this command will create a .Dq dangerously-dedicated label. -This command is normally run on a BSD slice rather than the compatibility +This command is normally run on a +.Bx +slice rather than the compatibility slice. If .Fl n @@ -439,7 +456,9 @@ In addition to restoring the volume labe If run on the compatibility slice this command will create a .Dq dangerously-dedicated label. -This command is normally run on a BSD slice rather than the compatibility +This command is normally run on a +.Bx +slice rather than the compatibility slice. .Pp The bootstrap commands always access the disk directly, so it is not necessary @@ -588,7 +607,7 @@ trackskew: 0 cylinderskew: 0 headswitch: 0 # milliseconds track-to-track seek: 0 # milliseconds -drivedata: 0 +drivedata: 0 16 partitions: # size offset fstype @@ -703,7 +722,7 @@ For file systems, use type .Cm 4.2BSD . For -.Tn HAMMER +.Xr HAMMER 5 file systems, use type .Cm HAMMER . For @@ -743,7 +762,9 @@ no longer snoop-adjusts the on-disklabel raw labels. .Nm is now responsible for adjusting the label when operating in raw mode. -Traditional (32 bit BSD) disklabels store offsets as absolute block numbers +Traditional (32 bit +.Bx ) +disklabels store offsets as absolute block numbers rather than slice-relative block numbers. If .Nm @@ -947,6 +968,25 @@ or .Dv FS_BOOT , .Nm will not install bootstrap code that overlaps it. +.Sh COMPATIBILITY +Due to +.Xr disklabel 5 +storing sector numbers in 32 bit format +.Nm +is restricted to 2TB, using the prevalent sector size of 512B. +.Xr disklabel64 5 labels should be used to partition larger disks. +.Pp +The various +.Bx Ns s +use slightly different versions of +.Bx +disklabels +and are not generally compatible. +The +.Dx +kernel can often use labels from other +.Bx Ns s +for read-only operation. .Sh SEE ALSO .Xr ccd 4 , .Xr disklabel 5 , @@ -955,16 +995,17 @@ will not install bootstrap code that ove .Xr diskinfo 8 , .Xr disklabel64 8 , .Xr fdisk 8 , +.Xr gpt 8 , .Xr vinum 8 .Sh BUGS Installing a .Xr disklabel64 8 -disklabel on a slice with a +label on a slice with a .Nm -disklabel installed requires reboot. First the existing disklabel -has to be overwritten, eg. by +label installed requires reboot. First the existing label +has to be overwritten, e.g. by .Xr dd 1 , -see above, then a reboot is required before the new disklabel can be installed. +see above, then a reboot is required before the new label can be installed. .Pp For the i386 architecture, the primary bootstrap sector contains an embedded @@ -994,7 +1035,9 @@ The .Nm utility does not perform all possible error checking. -Warning *is* given if partitions +Warning +.Em is +given if partitions overlap; if an absolute offset does not match the expected offset; if the .Dq c partition does not start at 0 or does not cover the entire slice; if a