partitions on software-raid

partitions on software-raid

[Norman Schmidt]

Hi!

Since noone has answered my last question yet:

Has anyone ever used partitions on a md device? It is possible to make 
them with fdisk, and fdisk shows their names as /dev/md0p1 (eg.). They 
are also shown in the partition table. But there are no /dev entries.

There are very few google hits, but no successful tries are documented.

Is this functionality implemented yet? I do not understand much C, so I 
gave up on understanding md.c in the kernel source tree. In the 
up-to-date list of major and minor numbers, there are no entries 
concerning partitions on md devices.

I think Neil Brown stated somewhere on this list that there could be up 
to 15 partitions for up to 16 md devices, but I don´t remember, couldn´t 
find it, and I don´t know wether he told how to make the devices or 
mount those partitions.

I am willing to test if this functionality exists, if not, I am forced 
to partition the underlying drives.

Thank you for the help, Norman Schmidt.

-- 
--

Norman Schmidt          Institut fuer Physikal. u. Theoret. Chemie
Dipl.-Chem.             Friedrich-Alexander-Universitaet
schmidt@naa.net         Erlangen-Nuernberg

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Re: partitions on software-raid

[Paul Clements]

Norman Schmidt wrote:

> Is this functionality implemented yet? I do not understand much C, so I

No, the md driver does not support partitions.


> I am willing to test if this functionality exists, if not, I am forced
> to partition the underlying drives.

With md, at least, that's your only option right now. You could maybe
look into lvm to do (non-standard) partitioning...

--
Paul

Re: partitions on software-raid

[David Haring]

Norman Schmidt wrote:
> Hi!
> 
> Since noone has answered my last question yet:
> 
> Has anyone ever used partitions on a md device? It is possible to make 
> them with fdisk, and fdisk shows their names as /dev/md0p1 (eg.). They 
> are also shown in the partition table. But there are no /dev entries.

I think it is possible, but it is nonstandard feature
(Neil Brown maintains patches for 2.4)

> There are very few google hits, but no successful tries are documented.
> 
> Is this functionality implemented yet? I do not understand much C, so I 
> gave up on understanding md.c in the kernel source tree. In the 
> up-to-date list of major and minor numbers, there are no entries 
> concerning partitions on md devices.
> 
> I think Neil Brown stated somewhere on this list that there could be up 
> to 15 partitions for up to 16 md devices, but I don´t remember, couldn´t 
> find it, and I don´t know wether he told how to make the devices or 
> mount those partitions.

see Neil's patches at
http://cgi.cse.unsw.edu.au/~neilb/patches/linux-stable/2.4.leading/2003-01-06:00/016MdPart
http://cgi.cse.unsw.edu.au/~neilb/patches/linux-stable/2.4.leading/2003-01-06:00/017MdpMajor

David Haring


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