2+ raid sets, sata and a missing hd question

2+ raid sets, sata and a missing hd question

[CaT]

Hi,

Lets say I have the following setup:

RAID 1 (as md1, md2, md3, md4, md5 for eg)
sda, sdb

RAID 5 (as md6)
sdc, sdd, sde, sdf, sdg

Seeing as how SATA drives can move around if one removes one from a set
(ie given sda, sdb, sdc, if sdb was removed sdc drops to sdb) would md6
come back up without problems if I were to remove either sda or sdb.

All md partitions are of type fd (Linux raid autodetect).

Thanks. :)

-- 
    "To the extent that we overreact, we proffer the terrorists the
    greatest tribute."
    	- High Court Judge Michael Kirby

Re: 2+ raid sets, sata and a missing hd question

[Luca Berra]

On Wed, Feb 15, 2006 at 01:45:21PM +1100, CaT wrote:
>Seeing as how SATA drives can move around if one removes one from a set
>(ie given sda, sdb, sdc, if sdb was removed sdc drops to sdb) would md6
>come back up without problems if I were to remove either sda or sdb.

if you configured mdadm correctly, you will have no problem :)

hint
echo DEVICE partitions >> /etc/mdadm.conf
mdadm -Esc partitions | grep ARRAY>> /etc/mdadm.conf

>All md partitions are of type fd (Linux raid autodetect).
>
this is surprisingly not at all relevant

L.

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Luca Berra -- bluca@comedia.it
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Re: 2+ raid sets, sata and a missing hd question

[CaT]

On Wed, Feb 15, 2006 at 07:50:28AM +0100, Luca Berra wrote:
> On Wed, Feb 15, 2006 at 01:45:21PM +1100, CaT wrote:
> >Seeing as how SATA drives can move around if one removes one from a set
> >(ie given sda, sdb, sdc, if sdb was removed sdc drops to sdb) would md6
> >come back up without problems if I were to remove either sda or sdb.
> 
> if you configured mdadm correctly, you will have no problem :)
> 
> hint
> echo DEVICE partitions >> /etc/mdadm.conf
> mdadm -Esc partitions | grep ARRAY>> /etc/mdadm.conf

So the md5 array will reconstruct itself after initial bootup where the
kernel reconstructs the raid1 (as well as it can) for booting?

> >All md partitions are of type fd (Linux raid autodetect).
>
> this is surprisingly not at all relevant

Awww. But I like it when the kernel just, well, does it all and makes it
all ready. :)

-- 
    "To the extent that we overreact, we proffer the terrorists the
    greatest tribute."
    	- High Court Judge Michael Kirby

Re: 2+ raid sets, sata and a missing hd question

[Mark Hahn]

> hint
> echo DEVICE partitions >> /etc/mdadm.conf
> mdadm -Esc partitions | grep ARRAY>> /etc/mdadm.conf
> 
> >All md partitions are of type fd (Linux raid autodetect).
> >
> this is surprisingly not at all relevant

I'm not sure about that.  I've accidentally shuffled disks before,
and 0xfd resulted in all the MD's coming to life again.  I never 
use /etc/mdadm.conf, since there doesn't seem to be much point...

regards, mark hahn.

Re: 2+ raid sets, sata and a missing hd question

[Luca Berra]

On Wed, Feb 15, 2006 at 06:44:29PM -0500, Mark Hahn wrote:
>> hint
>> echo DEVICE partitions >> /etc/mdadm.conf
>> mdadm -Esc partitions | grep ARRAY>> /etc/mdadm.conf
>> 
>> >All md partitions are of type fd (Linux raid autodetect).
>> >
>> this is surprisingly not at all relevant
>
>I'm not sure about that.  I've accidentally shuffled disks before,
>and 0xfd resulted in all the MD's coming to life again.  I never 
>use /etc/mdadm.conf, since there doesn't seem to be much point...

i did not speak about in-kernel autodetection.

don't cc me on list replies unless it is really important

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Luca Berra -- bluca@comedia.it
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