[gentoo-user] Partitions

[gentoo-user] Partitions

[Peter Humphrey]

Hello list,

Does it make sense to install a partition table on a RAID-1 device? I assume 
it would only include a single partition table, but it might prevent some 
programs from complaining they don't recognise the partition type. I have 
one such device for /boot and another for lvm2 volumes.

Secondly, has anyone here had problems with gparted? I tried to run it today 
to get a picture of my disk use, but it bombed out with "Assertion 
(metadata_length > 0) at dos.c:2305 in function add_logical_part_metadata 
failed."

I have a bug report prepared, but I wanted to check here before submitting 
it.

-- 
Rgds
Peter.

Re: [gentoo-user] Partitions

[Rich Freeman]

On Sat, Mar 21, 2015 at 9:52 AM, Peter Humphrey <peter@prh.myzen.co.uk> wrote:
>
> Does it make sense to install a partition table on a RAID-1 device?

When I was using mdadm I would do it all the time.  It is the easiest
way to do RAID with devices of different sizes.  You just set up
multiple arrays across partitions of the same sizes and then combine
everything with LVM.


-- 
Rich

Re: [gentoo-user] Partitions

[Peter Humphrey]

On Saturday 21 March 2015 11:18:44 Rich Freeman wrote:
> On Sat, Mar 21, 2015 at 9:52 AM, Peter Humphrey <peter@prh.myzen.co.uk> 
wrote:
> > Does it make sense to install a partition table on a RAID-1 device?
> 
> When I was using mdadm I would do it all the time.  It is the easiest
> way to do RAID with devices of different sizes.  You just set up
> multiple arrays across partitions of the same sizes and then combine
> everything with LVM.

Thanks Rich.

I see I wasn't clear: I meant /dev/mdX resulting from combining /dev/sd[ab]X 
- I assume you meant the same.

Interesting that the installation doc doesn't mention it though. Or it 
didn't when I used it to build this box.

-- 
Rgds
Peter.

Re: [gentoo-user] Partitions

[Rich Freeman]

On Sat, Mar 21, 2015 at 2:14 PM, Peter Humphrey <peter@prh.myzen.co.uk> wrote:
> On Saturday 21 March 2015 11:18:44 Rich Freeman wrote:
>> On Sat, Mar 21, 2015 at 9:52 AM, Peter Humphrey <peter@prh.myzen.co.uk>
> wrote:
>> > Does it make sense to install a partition table on a RAID-1 device?
>>
>> When I was using mdadm I would do it all the time.  It is the easiest
>> way to do RAID with devices of different sizes.  You just set up
>> multiple arrays across partitions of the same sizes and then combine
>> everything with LVM.
>
> Thanks Rich.
>
> I see I wasn't clear: I meant /dev/mdX resulting from combining /dev/sd[ab]X
> - I assume you meant the same.
>
> Interesting that the installation doc doesn't mention it though. Or it
> didn't when I used it to build this box.

Oh, I wouldn't install partitions on top of an md raid device.  I
probably would use it as an lvm physical volume though.

-- 
Rich

Re: [gentoo-user] Partitions

[Neil Bothwick]

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On Sat, 21 Mar 2015 18:14:38 +0000, Peter Humphrey wrote:

> I see I wasn't clear: I meant /dev/mdX resulting from
> combining /dev/sd[ab]X 

If you're creating a RAID array from partitions, you don't need to create
further partitions. The only time I would partition an md device is if it
were created from whole disks.


-- 
Neil Bothwick

Bagpipe for free: Stuff cat under arm. Pull legs, chew tail.

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Re: [gentoo-user] Partitions

[Peter Humphrey]

On Saturday 21 March 2015 21:01:14 Neil Bothwick wrote:
> On Sat, 21 Mar 2015 18:14:38 +0000, Peter Humphrey wrote:
> > I see I wasn't clear: I meant /dev/mdX resulting from
> > combining /dev/sd[ab]X
> 
> If you're creating a RAID array from partitions, you don't need to create
> further partitions. The only time I would partition an md device is if it
> were created from whole disks.

OK, so I'll just ignore those warnings from various programs about not 
recognising partition types.

Thanks to all who've helped. What a fine place this is!

-- 
Rgds
Peter.