RAID-5 expansion / harddisk replacement (with bigger disks) without total data-loss

Johnathan Conley jdc at nextjet.com
Sat Aug 23 10:45:01 CDT 2003


 

I have successfully used Symantec Ghost to move linux between different systems /w different drive configurations.

 

Of course the system is down while you do this - but usually if you're 24x7 you have 2+ machines clustered/balanced and you can convert them 1 at a time.

 

Good luck.

 

 

-----Original Message-----
From: René Hoffmann [mailto:hoffmann at chamaeleon.de] 
Sent: Friday, August 22, 2003 1:00 PM
To: linux-poweredge at dell.com
Subject: RAID-5 expansion / harddisk replacement (with bigger disks) without total data-loss

 

Hi,

First of all thanks to everyone helping my colleague 
Nicolai in this particular topic.

The overall suggestion is: don't do it.

For your background information:

The system is an internet server running 24x7, 
so our goal is to reduce downtimes (btw: that's 
the primary function of RAID-redundancy, isn't it?)

On the other side the load beside office-times is
low; lower performance (e.g. caused by rebuilds)
is no problem.

It´s also ok to have at last two partitions:
one 9 GB and one 27 GB. 


In order to be able to maintain the system,  I now
would like to understand, what's the specific problem:

Is it risky:

1) to replace one 9GB disk with a 36GB ?

2) to replace more than one disk with a 36GB ?

3) to replace even the last disk with a 36GB ?

- if it´s safe to do that until now, we would 
  have a 9GB container on 36 GB disks -

4) to grow the container size ?

- if that´s the point: what could we do alternatively - 

5) create another container on the left 27GB unused space ? 



Looking foreword to your answers

Greetings




René Hoffmann
Leiter Technik
 
Chamaeleon Aktiengesellschaft
für innovative Netzlösungen
Robert-Bosch-Str. 12 / Haus IV
D-56410 Montabaur
Hotline:  +49 26 02 - 10 16 9 - 160
Zentrale: +49 26 02 - 10 16 9 - 0
Telefon:  +49 26 02 - 10 16 9 - 154
Fax:      +49 26 02 - 10 16 9 - 101
Email: hoffmann at chamaeleon.de
http://www.chamaeleon.de






> Nicolai Schleifer <schleifer at chamaeleon.de> wrote:
> 
> > Hello,
> > 
> > I'd like to replace the four 9GB harddisks of container 1 in the example
> > below against 36GB harddisks without having a total data loss of that
> > container. The goal is to extend the overall size of that container from "(4 time 9GB)-raid-5_overhead" to "(4 times 36GB)-raid-5_overhead".
> > 
> > I think it should be possible, by first replacing all the 9GB harddisks,
> > one by one (like if they were broken and needed to be replaced) and after that by extending the container's size to the full extent that should be possible by then (found hints about that, using afacli commands "container reconfigure"/"container extend").
> > 
> > I'm currently reading this mailinglist about my planned expansion task,
> > to various different results. I can't find an example on the list which
> > matches my task. Any hints?
> > 
> > Example Configuration:
> > AFA0> container list
> > Executing: container list
> > Num          Total  Oth Chunk          Scsi   Partition
> > Label Type   Size   Ctr Size   Usage   B:ID:L Offset:Size
> > ----- ------ ------ --- ------ ------- ------ -------------
> >  0    Mirror 8.47GB            Open    0:00:0 64.0KB:8.47GB 
> >  /dev/sda             SYSTEM           0:01:0 64.0KB:8.47GB 
> > 
> >  1    RAID-5 25.4GB       64KB Open    0:02:0 64.0KB:8.47GB 
> >  /dev/sdb             DATA             0:03:0 64.0KB:8.47GB 
> >                                        0:04:0 64.0KB:8.47GB 
> >                                        0:05:0 64.0KB:8.47GB 
> > 
> > Maybe someone can tell me if it's possible at all. A recipe on how to do it would even be greater.
> > 
> > Thank you! :)
> > 
> > 
> > Greetings Nicolai
> > -- 
> > Nicolai Schleifer
> > Chamaeleon Aktiengesellschaft
> > fur innovative Netzlosungen
> > Robert-Bosch-Str. 12 / Haus IV
> > D-56410 Montabaur
> > Hotline:  +49 26 02 - 10 16 9 - 160
> > Zentrale: +49 26 02 - 10 16 9 - 0
> > Fax:      +49 26 02 - 10 16 9 - 101
> > Funk:     +49 177 - 32 08 60 7
> > Email: schleifer at chamaeleon.de
> > http://www.chamaeleon.de






 
 
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