[rescue] Mounting and Dumping

[Jonathan C. Patschke]

On Wed, 14 Jan 2004, Sheldon T. Hall wrote:

> In 1983 I wrote a backup program for CP/M, in BASIC, that would back up
> any size of hard drive, to any number of floppy disks, and arrange the
> files to fill the floppies as full as possible.  If I could do that, why
> can't the guys at [Sun|Microsoft|wherever] do something better twenty
> years later?

So, how did you solve the contention between multiple users and processes
of differing priority (possibly exceeding the backup tool's) reading from
and writing to a journalized filesystem under CP/M?

If you just want to copy files, tar works great.  If you want filesystem
metadata, and you want to ensure integrity and consistency on at least a
file-by-file basis (if not on a filesystem-wide basis), life gets
complicated.

> I wonder if they got more complaints about this than Sun gets.

I dump online filesystems without a problem all the time.  Sun
-recommends- it, but it's really not a big deal if you run your backups
while the system during periods of low load.

Now, if you're backing up huge files that may change at any point in
time (like, say, a database table file), you're SOL, which is why you
typically use a SQL-dump utility or perform DB backups with the database
offline.

-- 
Jonathan Patschke  ) "Some people grow out of the petty theft of
Elgin, TX         (   childhood.  Others grow up to be CEOs and
USA                )  politicians."                    --Phorist