( crossing with John's post, and largely consistent with it... :-) Ralph's right that you can probably use 'cp' rather than rsync, but it's not a great overhead and would mean that you could then do the same another time to keep b up to date with a. You need to have the 'recursive' option set for 'cp', but -a includes that so you're OK.
If you use rsync you have to watch out for the distinction between a directory as a file in itself and a directory as a directory as a folder of other files. The command you give above: sudo rsync -r -a sda3/home sdb4/home (from root directoiry '/' presumably) will give you a destination structure /sdb4/home/home/user1 and /sdb4/home/home/user2 if sdb4/home already exists. On the other hand, sudo rsync -r -a sda3/home/ sdb4/home should give you a destination structure /sdb4/home/user1 and / sdb4/home/user2 as will sudo rsync -r -a sda3/home/* sdb4/home On 21 July 2015 at 12:42, Ralph Corderoy <[email protected]> wrote: > Hi Clive, > > > sudo rsync -r -a sda3/home sdb4/home > > Since source and destination are on the same machine, and you're not > trying to update an old copy to match an original that's since changed, > you may as well use cp(1). > > Probably, > > sudo cp -a --preserve=all --sparse=always /home /mnt/sdb4/home > > assuming /dev/sdb4 is mounted at /mnt/sdb4, adjust to suit, and that > /mnt/sdb4/home doesn't already exist, e.g. another home will be put > inside it. (Please correct me if I'm wrong, everyone else. :-) > > > Reason is a partial upgrade of the operating system which is on sda1 > > of the first disc. > > So is this just a backup in case things go awry? > > > Will using rsync take long to move 52Gb of data? (1 or 2 hrs?) > > Quite a bit less than that, I'd have thought. > > > Is it safe to do this while sda is mounted or should I do it from a > > live disc? > > You need /dev/sda3 mounted so /home is visible as a bunch of directories > and files. From a live disk you could copy the sda3 partition to a > partition on sdb; that would be a byte for byte copy, not caring that > it has a filesystem on it. Depends what your end aim is. > > Cheers, Ralph. > > -- > Next meeting: Bournemouth, Tuesday, 2015-08-04 20:00 > Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ > New thread: mailto:[email protected] / CHECK IF YOU'RE REPLYING > Reporting bugs well: http://goo.gl/4Xue / TO THE LIST OR THE AUTHOR > -- best regards, 웃 Victor Churchill, Bournemouth -- Next meeting: Bournemouth, Tuesday, 2015-08-04 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread: mailto:[email protected] / CHECK IF YOU'RE REPLYING Reporting bugs well: http://goo.gl/4Xue / TO THE LIST OR THE AUTHOR
