On Friday June 4, robin@xxxxxxxxxxxxxx wrote:
> On Fri, June 4, 2004 7:29, Neil Brown said:
> > - Further support for partitionable arrays included "--auto=" option
> > and "auto=" config file entry which instructs mdadm to create the necessary
> > device files after allocating an unused array number.
>
> Neil,
>
> I am interpreting this to mean that I can create, for example, a large (e.g. 1TB) RAID5
> array and create smaller partitions (/home, /usr, etc) on top of the RAID5 array? Is
> this correct?
Yes, this is correct.
>
> Where can I read more about this?
Uhm.... Good question. The are brief hints in
man mdadm
and
man mdadm.conf
but I guess I should put something in:
man 4 md
In recent 2.6 kernels you can create partitionable md arrays.
The is no fixed major number. The major number can be found by
looking for "mdp" in /proc/devices.
There are 64 minor numbers for each array, allowing up to 63
partitions.
The simplest way to access this functionality is with
mdadm --create /dev/md/XX --auto=partition --level= ....
to create, or
mdadm --assemble /dev/md/XX --auto=partition .....
to assemble. Alternately "auto=partition" can be put in mdadm.conf.
If you do this, it will create device files:
/dev/md/XX the whole array
/dev/md/XX1 the first partition
/dev/md/XX2 the second partition
/dev/md/XX3 the third partition
/dev/md/XX4 the fourth partition
More (or less) partitions can be created using e.g. --auto=partition8
to create 8 partition device files.
The arrays will appear in /proc/mdstat as
md_dN
where N is the number that was chosen.
Then
cfdisk /dev/md/XX
will allow you to partition the array.
I hope this helps.
NeilBrown
>
> Thanks,
>
> R.
> --
> http://robinbowes.com
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