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Diffstat (limited to 'disk-utils/sfdisk.examples')
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diff --git a/disk-utils/sfdisk.examples b/disk-utils/sfdisk.examples new file mode 100644 index 000000000..13e671d48 --- /dev/null +++ b/disk-utils/sfdisk.examples @@ -0,0 +1,264 @@ +Examples of the use of sfdisk 3.0 (to partition a disk) +Input lines have fields <start>,<size>,<type>... - see sfdisk.8. +Usually no <start> is given, and input lines start with a comma. + +Before doing anything with a disk, make sure it is not in use; +unmount all its file systems, and say swapoff to its swap partitions. +(The final BLKRRPART ioctl will fail if anything else still uses +the disk, and you will have to reboot. It is easier to first make +sure that nothing uses the disk, e.g., by testing: + % umount /dev/sdb1 + % sfdisk -R /dev/sdb + BLKRRPART: Device or resource busy + * Device busy for revalidation (usage=2) + % swapoff /dev/sdb3 + % sfdisk -R /dev/sdb + * sdb: sdb1 < sdb5 sdb6 > sdb3 + % +Note that the starred messages are kernel messages, that may be +logged somewhere, or written to some other console. +In sfdisk 3.01 sfdisk automatically does this check, unless told not to.) + +1. One big partition: + sfdisk /dev/hda << EOF + ; + EOF + +(If there was garbage on the disk before, you may get error messages +like: `ERROR: sector 0 does not have an msdos signature' +and `/dev/hda: unrecognized partition'. This does not matter +if you write an entirely fresh partition table anyway.) + +The output will be: +----------------------------------------------------------------------- +Old situation: +... +New situation: +Units = cylinders of 208896 bytes, blocks of 1024 bytes, counting from 0 + + Device Boot Start End #cyls #blocks Id System +/dev/hda1 0+ 1023 1024- 208895+ 83 Linux native +Successfully wrote the new partition table + hda: hda1 +----------------------------------------------------------------------- +Writing and rereading the partition table takes a few seconds - +don't be alarmed if nothing happens for six seconds or so. + + +2. Three primary partitions: two of size 50MB and the rest: + sfdisk /dev/hda -uM << EOF + ,50 + ,50 + ; + EOF +----------------------------------------------------------------------- +New situation: +Units = megabytes of 1048576 bytes, blocks of 1024 bytes, counting from 0 + + Device Boot Start End MB #blocks Id System +/dev/hda1 0+ 50- 51- 51203+ 83 Linux native +/dev/hda2 50+ 100- 51- 51204 83 Linux native +/dev/hda3 100+ 203 104- 106488 83 Linux native +Successfully wrote the new partition table + hda: hda1 hda2 hda3 +----------------------------------------------------------------------- +/dev/hda1 is one block (in fact only half a block) shorter than +/dev/hda2 because its start had to be shifted away from zero in +order to leave room for the Master Boot Record (MBR). + + +3. A 1MB OS2 Boot Manager partition, a 50MB DOS partition, + and three extended partitions (DOS D:, Linux swap, Linux): + sfdisk /dev/hda -uM << EOF + ,1,a + ,50,6 + ,,E + ; + ,20,4 + ,16,S + ; + EOF +----------------------------------------------------------------------- + Device Boot Start End MB #blocks Id System +/dev/hda1 0+ 1- 2- 1223+ a OS/2 Boot Manager +/dev/hda2 1+ 51- 51- 51204 6 DOS 16-bit FAT >=32M +/dev/hda3 51+ 203 153- 156468 5 Extended +/dev/hda4 0 - 0 0 0 Empty +/dev/hda5 51+ 71- 21- 20603+ 4 DOS 16-bit FAT <32M +/dev/hda6 71+ 87- 17- 16523+ 82 Linux swap +/dev/hda7 87+ 203 117- 119339+ 83 Linux native +Successfully wrote the new partition table + hda: hda1 hda2 hda3 < hda5 hda6 hda7 > +----------------------------------------------------------------------- +All these rounded numbers look better in cylinder units: + % sfdisk -l /dev/hda +----------------------------------------------------------------------- + Device Boot Start End #cyls #blocks Id System +/dev/hda1 0+ 5 6- 1223+ a OS/2 Boot Manager +/dev/hda2 6 256 251 51204 6 DOS 16-bit FAT >=32M +/dev/hda3 257 1023 767 156468 5 Extended +/dev/hda4 0 - 0 0 0 Empty +/dev/hda5 257+ 357 101- 20603+ 4 DOS 16-bit FAT <32M +/dev/hda6 358+ 438 81- 16523+ 82 Linux swap +/dev/hda7 439+ 1023 585- 119339+ 83 Linux native +----------------------------------------------------------------------- +But still - why does /dev/hda5 not start on a cylinder boundary? +Because it is contained in an extended partition that does. +Of the chain of extended partitions, usually only the first is +shown. (The others have no name under Linux anyway.) But +these additional extended partitions can be made visible: + % sfdisk -l -x /dev/hda +----------------------------------------------------------------------- + Device Boot Start End #cyls #blocks Id System +/dev/hda1 0+ 5 6- 1223+ a OS/2 Boot Manager +/dev/hda2 6 256 251 51204 6 DOS 16-bit FAT >=32M +/dev/hda3 257 1023 767 156468 5 Extended +/dev/hda4 0 - 0 0 0 Empty + +/dev/hda5 257+ 357 101- 20603+ 4 DOS 16-bit FAT <32M + - 358 1023 666 135864 5 Extended + - 257 256 0 0 0 Empty + - 257 256 0 0 0 Empty + +/dev/hda6 358+ 438 81- 16523+ 82 Linux swap + - 439 1023 585 119340 5 Extended + - 358 357 0 0 0 Empty + - 358 357 0 0 0 Empty + +/dev/hda7 439+ 1023 585- 119339+ 83 Linux native + - 439 438 0 0 0 Empty + - 439 438 0 0 0 Empty + - 439 438 0 0 0 Empty +----------------------------------------------------------------------- + +Why the empty 4th input line? The description of the extended partitions +starts after that of the four primary partitions. +You force an empty partition with a ",0" input line, but here all +space was divided already, so the fourth partition became empty +automatically. + +How did I know about 4,6,a,E,S? Well, E,S,L stand for Extended, +Swap and Linux. The other values are hexadecimal and come from +the table: + % sfdisk -T + Id Name + + 0 Empty + 1 DOS 12-bit FAT + 2 XENIX root + 3 XENIX usr + 4 DOS 16-bit FAT <32M + 5 Extended + 6 DOS 16-bit FAT >=32M + 7 OS/2 HPFS or QNX or Advanced UNIX + 8 AIX data + 9 AIX boot or Coherent + a OS/2 Boot Manager + ... + + +4. Preserving the sectors changed by sfdisk. + % sfdisk -O save-hdd-partition-sectors /dev/hda + ... + will write the sectors overwritten by sfdisk to file. + If you notice that you trashed some partition, you may + be able to restore things by + % sfdisk -I save-hdd-partition-sectors /dev/hda + % + +5. Preserving some old partitions. + % sfdisk -N2 /dev/hda + ... + will only change the partition /dev/hda2, and leave the rest + unchanged. The most obvious application is to change an Id: + % sfdisk -N7 /dev/hda + ,,63 + % +----------------------------------------------------------------------- +Old situation: + + Device Boot Start End #cyls #blocks Id System +/dev/hda1 0+ 5 6- 1223+ a OS/2 Boot Manager +... +/dev/hda6 358+ 438 81- 16523+ 82 Linux swap +/dev/hda7 439+ 1023 585- 119339+ 83 Linux native + +New situation: + + Device Boot Start End #cyls #blocks Id System +/dev/hda1 0+ 5 6- 1223+ a OS/2 Boot Manager +... +/dev/hda6 358+ 438 81- 16523+ 82 Linux swap +/dev/hda7 439+ 1023 585- 119339+ 63 GNU HURD +----------------------------------------------------------------------- + Note that changing a logical partition into an empty partition + will decrease the number of all subsequent logical partitions. + +6. Deleting a partition. +At first I thought of having an option -X# for deleting partitions, +but there are several ways in which a partition can be deleted, and +it is probably better to handle this just as a general change. + % sfdisk -d /dev/hda > ohda +will write the current tables on the file `ohda'. +----------------------------------------------------------------------- +% cat ohda +# partition table of /dev/hda +unit: sectors + +/dev/hda1 : start= 1, size= 40799, Id= 5 +/dev/hda2 : start= 40800, size= 40800, Id=83 +/dev/hda3 : start= 81600, size= 336192, Id=83 +/dev/hda4 : start= 0, size= 0, Id= 0 +/dev/hda5 : start= 2, size= 40798, Id=83 +----------------------------------------------------------------------- +In order to delete the partition on /dev/hda3, edit this file +and feed the result to sfdisk again. +----------------------------------------------------------------------- +% emacs ohda +% cat ohda +# partition table of /dev/hda +unit: sectors + +/dev/hda1 : start= 1, size= 40799, Id= 5 +/dev/hda2 : start= 40800, size= 40800, Id=83 +/dev/hda3 : start= 0, size= 0, Id= 0 +/dev/hda4 : start= 0, size= 0, Id= 0 +/dev/hda5 : start= 2, size= 40798, Id=83 +% sfdisk /dev/hda < ohda +Old situation: +Units = cylinders of 208896 bytes, blocks of 1024 bytes, counting from 0 + + Device Boot Start End #cyls #blocks Id System +/dev/hda1 0+ 99 100- 20399+ 5 Extended +/dev/hda2 100 199 100 20400 83 Linux native +/dev/hda3 200 1023 824 168096 83 Linux native +/dev/hda4 0 - 0 0 0 Empty +/dev/hda5 0+ 99 100- 20399 83 Linux native +New situation: +Units = sectors of 512 bytes, counting from 0 + + Device Boot Start End #sectors Id System +/dev/hda1 1 40799 40799 5 Extended +/dev/hda2 40800 81599 40800 83 Linux native +/dev/hda3 0 - 0 0 Empty +/dev/hda4 0 - 0 0 Empty +/dev/hda5 2 40799 40798 83 Linux native +Successfully wrote the new partition table +% sfdisk -l -V /dev/hda + +Disk /dev/hda: 12 heads, 34 sectors, 1024 cylinders +Units = cylinders of 208896 bytes, blocks of 1024 bytes, counting from 0 + + Device Boot Start End #cyls #blocks Id System +/dev/hda1 0+ 99 100- 20399+ 5 Extended +/dev/hda2 100 199 100 20400 83 Linux native +/dev/hda3 0 - 0 0 0 Empty +/dev/hda4 0 - 0 0 0 Empty +/dev/hda5 0+ 99 100- 20399 83 Linux native +/dev/hda: OK +----------------------------------------------------------------------- +This is a good way of making changes: dump the current status +to file, edit the file, and feed it to sfdisk. +Preserving the file on some other disk could be useful: +if ever the MBR gets thrashed it can be used to restore +the old situation. |