Re: replacing drives

[Roberto Nunnari <roberto.nunnari@supsi.ch>]

Roberto Nunnari wrote:
> Robin Hill wrote:
>> The safest option would be:
>>  - add in the new disks
>>  - partition to at least the same size as your existing partitions (they
>>    can be larger)
>>  - add the new partitions into the arrays (they'll go in as spares)
>>  - grow the arrays to 4 members (this avoids any loss of redundancy)
>>  - wait for the resync to complete
>>  - install grub/lilo/syslinux to the new disks
>>  - fail and remove the old disk partitions from the arrays
>>  - shrink the arrays back down to 2 members
>>  - remove the old disks
>>
>> Then, if you're keeping the same number of partitions but increasing the
>> size:
> 
> Ok.. got here.
> 
>>  - grow the arrays to fill the partitions
>>  - grow the filesystems to fill the arrays
> 
> Now the scary part.. so.. here I believe I should give the following 
> commands:
> 
> mdadm --grow /dev/md0 --size=max
> mdadm --grow /dev/md1 --size=max
> mdadm --grow /dev/md2 --size=max
> 
> and after that
> 
> fsck /dev/md0
> fsck /dev/md1
> fsck /dev/md2
> 
> and
> 
> resize2fs /dev/md0
> resize2fs /dev/md1
> resize2fs /dev/md2
> 
> Correct?
> 
> 
> .. I still have a couple of questions:
> 
> 1) how do I know if there's a bitmap?
> 
> 2) at present /dev/md2 usage is 100%.. could that cause any problem?
> 
> 3) the new drives are 2TG drives.. As around one year ago had trouble on 
> linux (it was a server dated 2006 with CentOS 5) that would not handle 
> drives larger than 2TB.. I wander what happens if one day one drive 
> fails and the drive I'll buy to replace will be sold as 2TB but in 
> reality slightly larger than 2TB.. what will happen? Will linux fail 
> again to use a drive larger than 2TB?
> At present I'm on ubuntu 10.04, all software from standard distribution.
> 
> Pitfalls I should know?
> 
> Thank you very much
> Robi

Anybody on this, please?

I'd really appreciate some guidance, especially for these last steps.

Thank you and best regards.
Robi