Lustre discuss - Sep 2011 - Removing OSTs and OSS

Hi,

I have some ageing hardware I''d like to remove. This includes the OSS 
and the OSTs connected to it.

So, as far as I understand, I need to deactivate the OSTs on the MDS 
with `lctl --device <devno> deactivate`, copy out all the objects from 
the deactivated OST with lfs_migrate and finally, permanently deactivate 
the OSTs on all the clients and MDS with `lctl conf_param <OST 
name>.osc.active=0`. Am I missing something, or is that it?

Now for my real question: Once everything copied out, I''d like to 
permanently switch off and re-purpose the hardware. Do I need to do 
anything else, other than unmounting the OSTs and shutting down the OSS? 
As far as I can tell, the MDS still knows about the this OSS and OSTs, 
but will not try to use it. So will the removed OSS cause possible 
issues in future? If so, how do I fix it. With a --writeconf on MDS/OSS?

All this will happen on a Lustre 1.8.5 system.

Thanks in advance,
Deon

Once the OSTs are deactivated you should mount them as ldiskfs and copy  out the
last_rcvd, O/0/LAST_ID, and CONFIGS/mountdata files for safe keeping for when
you want to add new OSTs. You can live without them, but it is easier to have
them.


Cheers, Andreas

On 2011-09-05, at 10:21 AM, Deon Borman <deon at blackginger.tv> wrote:
> Hi,
> 
> I have some ageing hardware I''d like to remove. This includes the
OSS
> and the OSTs connected to it.
> 
> So, as far as I understand, I need to deactivate the OSTs on the MDS 
> with `lctl --device <devno> deactivate`, copy out all the objects
from
> the deactivated OST with lfs_migrate and finally, permanently deactivate 
> the OSTs on all the clients and MDS with `lctl conf_param <OST 
> name>.osc.active=0`. Am I missing something, or is that it?
> 
> Now for my real question: Once everything copied out, I''d like to 
> permanently switch off and re-purpose the hardware. Do I need to do 
> anything else, other than unmounting the OSTs and shutting down the OSS? 
> As far as I can tell, the MDS still knows about the this OSS and OSTs, 
> but will not try to use it. So will the removed OSS cause possible 
> issues in future? If so, how do I fix it. With a --writeconf on MDS/OSS?
> 
> All this will happen on a Lustre 1.8.5 system.
> 
> Thanks in advance,
> Deon
> 
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