mirror of
https://github.com/torvalds/linux.git
synced 2024-12-21 02:21:36 +00:00
1da177e4c3
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!
103 lines
3.6 KiB
Plaintext
103 lines
3.6 KiB
Plaintext
|
|
LDM - Logical Disk Manager (Dynamic Disks)
|
|
------------------------------------------
|
|
|
|
Overview
|
|
--------
|
|
|
|
Windows 2000 and XP use a new partitioning scheme. It is a complete
|
|
replacement for the MSDOS style partitions. It stores its information in a
|
|
1MiB journalled database at the end of the physical disk. The size of
|
|
partitions is limited only by disk space. The maximum number of partitions is
|
|
nearly 2000.
|
|
|
|
Any partitions created under the LDM are called "Dynamic Disks". There are no
|
|
longer any primary or extended partitions. Normal MSDOS style partitions are
|
|
now known as Basic Disks.
|
|
|
|
If you wish to use Spanned, Striped, Mirrored or RAID 5 Volumes, you must use
|
|
Dynamic Disks. The journalling allows Windows to make changes to these
|
|
partitions and filesystems without the need to reboot.
|
|
|
|
Once the LDM driver has divided up the disk, you can use the MD driver to
|
|
assemble any multi-partition volumes, e.g. Stripes, RAID5.
|
|
|
|
To prevent legacy applications from repartitioning the disk, the LDM creates a
|
|
dummy MSDOS partition containing one disk-sized partition.
|
|
|
|
|
|
Example
|
|
-------
|
|
|
|
Below we have a 50MiB disk, divided into seven partitions.
|
|
N.B. The missing 1MiB at the end of the disk is where the LDM database is
|
|
stored.
|
|
|
|
Device | Offset Bytes Sectors MiB | Size Bytes Sectors MiB
|
|
-------+----------------------------+---------------------------
|
|
hda | 0 0 0 | 52428800 102400 50
|
|
hda1 | 51380224 100352 49 | 1048576 2048 1
|
|
hda2 | 16384 32 0 | 6979584 13632 6
|
|
hda3 | 6995968 13664 6 | 10485760 20480 10
|
|
hda4 | 17481728 34144 16 | 4194304 8192 4
|
|
hda5 | 21676032 42336 20 | 5242880 10240 5
|
|
hda6 | 26918912 52576 25 | 10485760 20480 10
|
|
hda7 | 37404672 73056 35 | 13959168 27264 13
|
|
|
|
The LDM Database may not store the partitions in the order that they appear on
|
|
disk, but the driver will sort them.
|
|
|
|
When Linux boots, you will see something like:
|
|
|
|
hda: 102400 sectors w/32KiB Cache, CHS=50/64/32
|
|
hda: [LDM] hda1 hda2 hda3 hda4 hda5 hda6 hda7
|
|
|
|
|
|
Compiling LDM Support
|
|
---------------------
|
|
|
|
To enable LDM, choose the following two options:
|
|
|
|
"Advanced partition selection" CONFIG_PARTITION_ADVANCED
|
|
"Windows Logical Disk Manager (Dynamic Disk) support" CONFIG_LDM_PARTITION
|
|
|
|
If you believe the driver isn't working as it should, you can enable the extra
|
|
debugging code. This will produce a LOT of output. The option is:
|
|
|
|
"Windows LDM extra logging" CONFIG_LDM_DEBUG
|
|
|
|
N.B. The partition code cannot be compiled as a module.
|
|
|
|
As with all the partition code, if the driver doesn't see signs of its type of
|
|
partition, it will pass control to another driver, so there is no harm in
|
|
enabling it.
|
|
|
|
If you have Dynamic Disks but don't enable the driver, then all you will see
|
|
is a dummy MSDOS partition filling the whole disk. You won't be able to mount
|
|
any of the volumes on the disk.
|
|
|
|
|
|
Booting
|
|
-------
|
|
|
|
If you enable LDM support, then lilo is capable of booting from any of the
|
|
discovered partitions. However, grub does not understand the LDM partitioning
|
|
and cannot boot from a Dynamic Disk.
|
|
|
|
|
|
More Documentation
|
|
------------------
|
|
|
|
There is an Overview of the LDM online together with complete Technical
|
|
Documentation. It can also be downloaded in html.
|
|
|
|
http://linux-ntfs.sourceforge.net/ldm/index.html
|
|
http://linux-ntfs.sourceforge.net/downloads.html
|
|
|
|
If you have any LDM questions that aren't answered on the website, email me.
|
|
|
|
Cheers,
|
|
FlatCap - Richard Russon
|
|
ldm@flatcap.org
|
|
|