dump and ext3

Malcolm Kay malcolm.kay at internode.on.net
Fri Jul 2 14:07:28 UTC 2004


On Friday 02 July 2004 08:55, Ed Wilts wrote:
> On Fri, Jul 02, 2004 at 02:14:48AM +0930, Malcolm Kay wrote:
> > ? Ad Wilts
>
> s/A/E

Sorry about that. A miskey.

>
> > From these I gather dump might work sometimes but is generally
> > messy and unreliable.
> >
> > I would have expected that backup would be have been a stable
> > and core part of any system.
>
> It is.  Just because dump doesn't work doesn't mean that backups aren't
> stable.  dump is just a distributor-supplied utility.
>

I am told, perhaps wrongly, that linux is a kernel only and that I need 
distributor-supplied utilities to make a real OS. So just which
distributor-supplied utilities make up the core OS?

On most unix systems dump/restore are a part of the core OS. 
 
> > I must say your responses have left me in something of a
> > quandary. While one might set up some exotic backup mechanism
> > it is not really very convenient to have to treat 2 linux
> > machines in a network of 25 or so as special cases.
>
> There are many other reliable backup tools.  We use NetBackup at work.
> Other people use a lot of different utilities.  Red Hat Linux ships with
> amanda.
>

Clearly amanda is not part of the core RH OS. It is not installed with
a default installation of RH 9 (dump/restore are).

> > Which brings up another issue. Under linux can I create and
> > mount a file system within a file on an existing file system
> > rather than on a separate disk partition? This would allow me
> > to at least try a restore operation using the space available
> > in the current file system.
>
> Look at mount --bind.  I think this does what I think you want.
>

Not really; this is something different. I was looking for something
like 'vnconfig' from BSD. With this I can create a fs of any type known
to the operating system nested within a regular file.
An extract from the man page->

SYNOPSIS
     vnconfig [-cdeguvTZ] [-s option[,option...]] [-r option[,option...]]
              [-S value] special_file [regular_file] [feature]
     vnconfig -a [-cdeguv] [-s option] [-r option] [-f config_file]

DESCRIPTION
     The vnconfig command configures and enables vnode pseudo disk devices.
     The first form of the command will associate the special file
     special_file with the regular file regular_file allowing the latter to be
     accessed as though it were a disk.  Hence a regular file within the
     filesystem can be used for swapping or can contain a filesystem that is
     mounted in the name space.  If you want to use swap backing store for
     your device instead of a file, you can leave regular_file out and specify
     the size of the block device with the -S option.

> --
> Ed Wilts, RHCE
> Mounds View, MN, USA
> mailto:ewilts at ewilts.org
> Member #1, Red Hat Community Ambassador Program

Malcolm Kay





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