[vdr] Re: Disk suggestions?

[Malcolm Caldwell <malcolm.caldwell@ntu.edu.au>]

On Mon, 2002-07-22 at 02:45, Emil Naepflein wrote:
> On Sat, 20 Jul 2002 12:23:05 +0200, Carsten Koch <Carsten.Koch@icem.de>
> wrote:
> 
> > At our main development office, we have an external IDE-to-SCSI RAID,
> > which, as a surprise to everyone, has turned out to be very unreliable.
> > Of course you are safe against one disk failing. But we had other problems,
> > like the RAID itself failing, second disk failing before recovery was 
> > complete, two power supplies failing, firmware problems, etc.
> 
> Very bad product!
> 
> > 
> > IMHO, as a home user you want individual disks with individual mount
> > points and file systems. No LVM, no RAID. 
> 
> Wrong. As a home user I want to be save against the failure of one disk
> and exactly this is achieved by software raid.
>
> > So, if one disk fails, you lose at most the data on that one disk. 
> 
> That's already very bad. If one disk fails with software raid you loose
> nothing. 

Wrong.  It all depends on the number of disks and your raid
configuration.  Lets say you have two disks:

With two disks, all you can sensibly do is mirroring (RAID1).  There may
be some home users around that can afford two big disks, and value their
recordings enough.  (I am not one of them)

IMHO You are better using the two disks to their full capacity and
making two /videoX volumes.

If instead you make two disk look like one (RAID0 or LVM etc) you are
twice as vulnerable to data loss from a single disk failure. 

With more disks it is less of an issue, but RAID > 0 will always mean
less storage than if each disk was its own volume.  It is a judgment of
$$$ vs how much you value your video data.

> > That also makes you much more flexible in regard to reconfigurations,
> > testing a new Linux distribution, adding/changing disks, etc.
> 
> It is also very easy with software raid.
> 
> Emil
-- 
Malcolm Caldwell <malcolm.caldwell@ntu.edu.au>
Northern Territory University