UUID's

UUID's

[Richard Scobie]

If I have specified an array in mdadm.conf using UUID's:

ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371

and I replace a failed drive in the array, will the new drive be given 
the previous UUID, or do I need to upate the mdadm.conf entry?

Regards,

Richard

Re: UUID's

[dean gaudet]

On Sat, 9 Sep 2006, Richard Scobie wrote:

> If I have specified an array in mdadm.conf using UUID's:
> 
> ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
> 
> and I replace a failed drive in the array, will the new drive be given the
> previous UUID, or do I need to upate the mdadm.conf entry?

once you do the "mdadm /dev/mdX -a /dev/newdrive" the new drive will have 
the UUID.  no need to update the mdadm.conf for the UUID...

however if you're using "DEVICE foo" where foo is not "partitions" then 
you should make sure foo includes the new drive.  ("DEVICE partitions" is 
recommended.)

-dean

Re: UUID's

[Richard Scobie]

dean gaudet wrote:
> 
> On Sat, 9 Sep 2006, Richard Scobie wrote:
> 
> 
>>If I have specified an array in mdadm.conf using UUID's:
>>
>>ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
>>
>>and I replace a failed drive in the array, will the new drive be given the
>>previous UUID, or do I need to upate the mdadm.conf entry?
> 
> 
> once you do the "mdadm /dev/mdX -a /dev/newdrive" the new drive will have 
> the UUID.  no need to update the mdadm.conf for the UUID...
> 
> however if you're using "DEVICE foo" where foo is not "partitions" then 
> you should make sure foo includes the new drive.  ("DEVICE partitions" is 
> recommended.)

Thanks Dean,

I am setting up a Fedora 5 machine, which I configured to use RAID1 for 
all partions during the install and the resulting madadm.conf it 
generated is:

DEVICE partitions
MAILADDR root
ARRAY /dev/md3 super-minor=3
ARRAY /dev/md1 super-minor=1
ARRAY /dev/md4 super-minor=4
ARRAY /dev/md0 super-minor=0
ARRAY /dev/md2 super-minor=2

To remove all doubt about what is assembled where, I though going to:

DEVICE partitions
MAILADDR root
ARRAY /dev/md3 UUID=xyz etc.

would be more secure.

Is this correct thinking on my part?

Regards,

Richard

Re: UUID's

[dean gaudet]

On Sat, 9 Sep 2006, Richard Scobie wrote:

> To remove all doubt about what is assembled where, I though going to:
> 
> DEVICE partitions
> MAILADDR root
> ARRAY /dev/md3 UUID=xyz etc.
> 
> would be more secure.
> 
> Is this correct thinking on my part?

yup.

mdadm can generate it all for you... there's an example on the man page.  
basically you just want to paste the output of "mdadm --detail --scan 
--config=partitions" into your mdadm.conf.

-dean