diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/ldm.txt |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/ldm.txt')
-rw-r--r-- | Documentation/ldm.txt | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/Documentation/ldm.txt b/Documentation/ldm.txt new file mode 100644 index 000000000000..e266e11c19a3 --- /dev/null +++ b/Documentation/ldm.txt | |||
@@ -0,0 +1,102 @@ | |||
1 | |||
2 | LDM - Logical Disk Manager (Dynamic Disks) | ||
3 | ------------------------------------------ | ||
4 | |||
5 | Overview | ||
6 | -------- | ||
7 | |||
8 | Windows 2000 and XP use a new partitioning scheme. It is a complete | ||
9 | replacement for the MSDOS style partitions. It stores its information in a | ||
10 | 1MiB journalled database at the end of the physical disk. The size of | ||
11 | partitions is limited only by disk space. The maximum number of partitions is | ||
12 | nearly 2000. | ||
13 | |||
14 | Any partitions created under the LDM are called "Dynamic Disks". There are no | ||
15 | longer any primary or extended partitions. Normal MSDOS style partitions are | ||
16 | now known as Basic Disks. | ||
17 | |||
18 | If you wish to use Spanned, Striped, Mirrored or RAID 5 Volumes, you must use | ||
19 | Dynamic Disks. The journalling allows Windows to make changes to these | ||
20 | partitions and filesystems without the need to reboot. | ||
21 | |||
22 | Once the LDM driver has divided up the disk, you can use the MD driver to | ||
23 | assemble any multi-partition volumes, e.g. Stripes, RAID5. | ||
24 | |||
25 | To prevent legacy applications from repartitioning the disk, the LDM creates a | ||
26 | dummy MSDOS partition containing one disk-sized partition. | ||
27 | |||
28 | |||
29 | Example | ||
30 | ------- | ||
31 | |||
32 | Below we have a 50MiB disk, divided into seven partitions. | ||
33 | N.B. The missing 1MiB at the end of the disk is where the LDM database is | ||
34 | stored. | ||
35 | |||
36 | Device | Offset Bytes Sectors MiB | Size Bytes Sectors MiB | ||
37 | -------+----------------------------+--------------------------- | ||
38 | hda | 0 0 0 | 52428800 102400 50 | ||
39 | hda1 | 51380224 100352 49 | 1048576 2048 1 | ||
40 | hda2 | 16384 32 0 | 6979584 13632 6 | ||
41 | hda3 | 6995968 13664 6 | 10485760 20480 10 | ||
42 | hda4 | 17481728 34144 16 | 4194304 8192 4 | ||
43 | hda5 | 21676032 42336 20 | 5242880 10240 5 | ||
44 | hda6 | 26918912 52576 25 | 10485760 20480 10 | ||
45 | hda7 | 37404672 73056 35 | 13959168 27264 13 | ||
46 | |||
47 | The LDM Database may not store the partitions in the order that they appear on | ||
48 | disk, but the driver will sort them. | ||
49 | |||
50 | When Linux boots, you will see something like: | ||
51 | |||
52 | hda: 102400 sectors w/32KiB Cache, CHS=50/64/32 | ||
53 | hda: [LDM] hda1 hda2 hda3 hda4 hda5 hda6 hda7 | ||
54 | |||
55 | |||
56 | Compiling LDM Support | ||
57 | --------------------- | ||
58 | |||
59 | To enable LDM, choose the following two options: | ||
60 | |||
61 | "Advanced partition selection" CONFIG_PARTITION_ADVANCED | ||
62 | "Windows Logical Disk Manager (Dynamic Disk) support" CONFIG_LDM_PARTITION | ||
63 | |||
64 | If you believe the driver isn't working as it should, you can enable the extra | ||
65 | debugging code. This will produce a LOT of output. The option is: | ||
66 | |||
67 | "Windows LDM extra logging" CONFIG_LDM_DEBUG | ||
68 | |||
69 | N.B. The partition code cannot be compiled as a module. | ||
70 | |||
71 | As with all the partition code, if the driver doesn't see signs of its type of | ||
72 | partition, it will pass control to another driver, so there is no harm in | ||
73 | enabling it. | ||
74 | |||
75 | If you have Dynamic Disks but don't enable the driver, then all you will see | ||
76 | is a dummy MSDOS partition filling the whole disk. You won't be able to mount | ||
77 | any of the volumes on the disk. | ||
78 | |||
79 | |||
80 | Booting | ||
81 | ------- | ||
82 | |||
83 | If you enable LDM support, then lilo is capable of booting from any of the | ||
84 | discovered partitions. However, grub does not understand the LDM partitioning | ||
85 | and cannot boot from a Dynamic Disk. | ||
86 | |||
87 | |||
88 | More Documentation | ||
89 | ------------------ | ||
90 | |||
91 | There is an Overview of the LDM online together with complete Technical | ||
92 | Documentation. It can also be downloaded in html. | ||
93 | |||
94 | http://linux-ntfs.sourceforge.net/ldm/index.html | ||
95 | http://linux-ntfs.sourceforge.net/downloads.html | ||
96 | |||
97 | If you have any LDM questions that aren't answered on the website, email me. | ||
98 | |||
99 | Cheers, | ||
100 | FlatCap - Richard Russon | ||
101 | ldm@flatcap.org | ||
102 | |||