Re: Any pros or cons of using full disk versus partitons?

[David Brown <david.brown@hesbynett.no>]

On 13/04/11 22:21, David Miller wrote:
> From: "Matthew Tice"<mjtice@gmail.com>
> Date: Wed, 13 Apr 2011 13:38:39 -0600
>
>> So of course it technically doesn't matter but are there certain
>> (non-apparent) repercussions for choosing one over the other?  It seems to
>> save a couple steps by using the whole disk (not having to partition) - but
>> is that it?  One thing I'm thinking about the pros of using partitions is if
>> all your disks (or some) are different sizes - then you can set the
>> partition sizes the same.
>
> First, you sent this to "linux-raid-owner" instead of just
> "linux-raid".  The former goes to me, not to the mailing list.
>
> I've corrected it in the CC:
>
> Second, to answer your question, for some disk label variants you
> risk over-writing the disk label if you use the whole device
> as part of your RAID volume.  This definitely will happen, for
> example, with Sun disk labels.

Using whole disks in the raid will make it easier for replacing disks - 
you don't have to worry about partitioning them.  You can just plug them 
in and use them.  If you have some sort of monitoring scripts and hot 
plug disks, you may be able to avoid any interaction at all on disk 
replacement.

On the other hand, using partitions gives you lots more flexibility. 
You can do things such as use a small partition on each disk to form a 
raid10 array for swap, while using a bigger partition for data.  Or 
perhaps you want a very small partition on each disk as a wide raid1 
mirror, for your /boot (not that you need so much safety for /boot, but 
that it's easier to boot from a raid1 with metadata format 0.90 than 
from other raid types).