Adding new disks, include in volume group

[Paul Howarth]

Scot L. Harris wrote:
> I have built file systems across multiple drives before but that was
> done during install of the system.  
> 
> BTW: how much of a problem is it with multiple drive file systems when
> one of those drives fails?  Assumption here is that no raid is being
> used for that volume.

It's a big problem, and the severity depends on whether data you need to 
access is on the broken drive. I personally don't use non-mirrored 
multi-disk filesystems for anything of value, because I've had enough 
drives fail on me over the years that I feel the risk isn't worth it. 
However, I'd be more comfortable with it if it was say a pair of 
RAID1-mirrored drives added to a volume containing another pair of 
RAID1-mirrored drives (i.e. four drives in total). That could survive 
one (or possibly two) drive failures. You could mix and match with 
different RAID setups if you have lots of drives.

> And is a chance of such a failure a multiple of the drives in the
> volume?  Or is it higher?

I'm not a statistician but given an even distribution of data across the 
drives (which may not be the case), I'd think the chances rise linearly 
with each added drive.

Paul.