[sclug] hot drives

[Alex Butcher]

On Tue, 20 Jun 2006, Keith Edmunds wrote:

>
>> And you can't
>> partition a /dev/mdX directly; you need to use LVM to do this, which slows
>> things more and seems unnecessarily complex to me, but it's the way to do
>> it (I'm told) and it's how I have my server.
>
> While it's true that you can't sub-partition a /dev/mdX device, you can
> create more than one on a physical pair of disks (assuming RAID-1). I
> quite frequently create five /dev/mdX devices on a pair of disks. I've
> never really seen the attraction of LVM - it seems to provide little
> benefit for the cost of complicating the disk subsystem, particularly if
> a disk error occurs. I like to keep the disk subsystem simple!

The major advantage of LVM is dynamic (re)allocation of space for logical
volumes. Given how large modern discs are, an allocation error at install
time by the administrator of, say 10%, can represent a significant amount of
wasted space that would be useful if allocated to a different filesystem.

Of course, you can fake this all up using symlinks and the like, but IMHO,
that is even less simple than using LVM, in the long run, and on systems
where there is more than one sysadmin (or that single sysadmin is a bit
forgetful, like me).

Best Regards,
Alex.
-- 
Alex Butcher, Bristol UK.                           PGP/GnuPG ID:0x5010dbff

"[T]he whole point about the reason why I think it is important we go for
identity cards and an identity database today is that identity fraud and
abuse is a major, major problem. Now the civil liberties aspect of it, look
it is a view, I don't personally think it matters very much."
  - Tony Blair, 6 June 2006 <http://www.number-10.gov.uk/output/Page9566.asp>