Subject: Re: Two large disks
To: Simon Truss <simon@bigblue.demon.co.uk>
From: Richard Rauch <rkr@olib.org>
List: netbsd-help
Date: 11/29/2004 18:07:21
On Mon, Nov 29, 2004 at 11:30:00PM +0000, Simon Truss wrote:
 [...]
> > 1 Eventually using all 240GB.
> > 2 Not having to rebuild the filesystem from scratch
> >   in order to use both drives in one filesystem later.
> > 3 Reliability/redundancy of data/drives in the short
> >   term.
> > 4 Speed.
 [...]
> > * Anything I might not have considered (there's always
> >   something).
> 
> :-) yes the computer that writes the program you haven't
> asked for yet.

(^&


> >>vinum might be what you are looking for here. searching for
> >>Logical Volume Manager or LVM should get you some hits.
> >
> >
> >Okay, I've heard of that.  I never looked into it before.  I'll
> >have a look at it.  (^&
> >
> >If it lets me do #3 in the list above, and then eventually
> >give up #3 and get #1 and #2, then that's just what I need.
> 
> an LVM should get you 1 and 2, 4 should not get you any penalty.
> 3 is not addressed by LVM, only RAID or backups. RAID will get

I'm looking at the man-page for it now, but get the feeling that
I should be reading a printed paper instead of a man-page.


> you 3 and 4. I may be wrong here but I think only jfs and xfs
> enable extension of a live file system (linux).

If by "live" you mean while it's mounted, I don't need that.


> If you were to accept a read only filled drive when you add the
> second, a cheap and cheerful option is the union fs (mount_union).
 [...]

I hadn't thought of that.  This is a good idea.  So I can mirror
the disk today, and union mount it tomorrow.  (^&


> Having almost lost a 1TB file system recently I am thankful I
> placed reliability on the core components high on my list.

Well, the vast bulk of my data at the moment will be readily
recoverable, for a given value of "readily", and very static.

What is not readily recoverable should fit into a neat little
.tar archive that I can shove over the network to one of the
other systems, once a night.

If that fails to be true at some point, I can rethink my
storage layout.


 [...]
> Its nice, I can actually answer some questions on this list :-)
> Thanks.

(^&

Glad to be of "service".


-- 
  "I probably don't know what I'm talking about."  http://www.olib.org/~rkr/