[CentOS] Re: IDE RAID support -- clarification ...
Bryan J. Smith
b.j.smith at ieee.org
Fri Jul 22 12:51:10 UTC 2005
"Bryan J. Smith" <b.j.smith at ieee.org> wrote:
> ??? I thought XP Pro can use LDM and striping/mirroring, just
> like Windows 2000 Pro ???
Just FYI, you have to use a Logical Disk Manager (LDM)
Disk Label** (aka "Dynamic Disk") to use the software RAID
features of Windows 2000 Pro and XP Pro (not sure about
XP Home, what it offers).
This is a safety feature, as legacy BIOS/DOS Disk Labels
(aka "Basic Disk" -- i.e., old Primary/Extended/Logical
disk slices) can store inter-Disk Slice** dependencies/
associations.
LDM Disk Labels show up as a Disk Slice of type 42h in a
legacy BIOS/DOS Disk Label.
It's the same reason why you should use a Logical Volume
Management (LVM) Disk Slice when you use Linux's Software
RAID, even when using the Multi Disk (MD) for your RAID.
It will store Disk Slice associations, unlike a legacy
BIOS/DOS Disk Label.
-- Bryan
**NOTE: I'm purposely using established UNIX terminology,
instead of PC:
Disk Slice ~ Partition
Disk Label ~ Partition Table
Disk Labels can be encapsulated inside of Disk Slices. E.g., the
"Extended" primary partition is really a new Disk Label (with
"Logical" partitions) inside of a Disk Slice. Same deal with BSD
Disk Labels, NT5+ (2000+) LDM Disk Labels, Linux LVM Disk Labels,
etc... The legacy BIOS/DOS Disk Label has 0 storage other than
the Disk Slices themselves (other than MBR and the partition
table itself -- no meta-data, no journal, no geometry, etc...).
--
Bryan J. Smith mailto:b.j.smith at ieee.org
Sent from Yahoo Mail (please excuse any missing headers)
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