copying "a" partitions

[George Robbins]

In article <20692 at dartvax.Dartmouth.EDU> steve at avalon.dartmouth.edu (Steve Campbell) writes:
> Having a disk partition table on each disk pack (see chpt(8)) is a great
> improvement over having the partition layout coded into the driver, but 
> there is one little drawback.  It used to be possible to make backup
> copies of the root partition, 0a, by using dd(1) to copy /dev/r??0a to
> /dev/r??1a or any other "a" partition.  This was fast (less than a minute
> on RA81's) and on several occasions saved me many hours of work.  But now
> with the disk partition table in the superblock, you can't use dd(1) this
> way unless the two disks have identical partition tables, since the
> tables get copied, too, and...  
> 
> I haven't yet found a good alternative for making disk-to-disk copies
> of the root file system.  Pipes using tar(1) or dump/restore are much
> slower and have other disadvantages like too much operator intervention
> being required.  Does anyone have any suggestions?

Yes, this is a problem.  The simple solution is just to standardize on
parition sizes and drive types, at least between the system disk and the
place you like to do your root backups.

I usually do an occasional tape dump and restore, but have used a pipe on
occasion.  For a normal (7 or 15MB) root parition it's not that slow, and
as far as I can remember doesn't require any "operator intervention"...

#! /bin/sh
umount blah
newfs blah blah
mount blah
dump 0f - / | (cd blah; restore rf -)

done?

restore r is silent, restore x asks silly questions.  8-)

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr at cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)