topic Re: Differences...advantages mv vs. find in Operating System - HP-UX

Differences...advantages mv vs. find

Richard Briggs — Wed, 27 Jun 2001 14:30:37 GMT

I'm moving a lot of data/subdirs from one place to another: There's a little discussion here and I'd like your $0.02

is there any difference and/or advantage when moving all the contents of a directory to another directory using either:

mv * /newdir

versus

find . -xdev | cpio -pdmuvx /newdir

Thanks

PS: If you have a different/better/favorite way ... chime in.

Richard

Re: Differences...advantages mv vs. find

Volker Borowski — Wed, 27 Jun 2001 14:41:33 GMT

Hello,

if /newdir belongs to the same filesystem, mv just changes the inodes, no physical move happens while cpio actually reads and writes data.

If it is on diffrent filesystems, i see no real difference in the result.

Volker

Re: Differences...advantages mv vs. find

Bill McNAMARA_1 — Wed, 27 Jun 2001 14:43:32 GMT

hmmmm in terms of command line I prefer the mv!

Did you actually measure with time which one is best.. in terms of performance.

Later,
Bill

Re: Differences...advantages mv vs. find

Richard Briggs — Wed, 27 Jun 2001 14:46:45 GMT

Bill...

Both took a long time... so I can't say that there was any measurable difference....except to say that after the find command was done... I had to go back and rm the copied data. That took longer, considering the mv command (once completed) "deletes" the "copied" files.

Re: Differences...advantages mv vs. find

Volker Borowski — Wed, 27 Jun 2001 15:07:07 GMT

Richard,

Do you have to do this action frequently ?
I would go for seperate filesystems in this case:

umount /last_weeks
newfs "last_week_rlvol"

umount /this_week
mount "last_week_lvol" on /this_week
mount "this_week_lvol" on /last_week

with this, you could quickly toggle two filesystems.

Volker

Re: Differences...advantages mv vs. find

Richard Briggs — Wed, 27 Jun 2001 15:10:41 GMT

No.. this was a one time thing...I had a huge filesystem of MIB data growing beyond the limits of my vg00 pv's so I decided just to break out the underlying mib data to a new lvol on vg01... to do that, I had to create the new lvol and then mv/cp/find... all the data and get it over to the new lvol. That's all. However, your tip is noted, and will come in handy... thanks!

Re: Differences...advantages mv vs. find

Rodney Hills — Wed, 27 Jun 2001 15:23:00 GMT

if "mv * /newdir" is only moving files you are ok.

if it includes subdirectories and you are crossing file systems, I don't think "mv" will allow it.

If I have the room, I opt to copy rather than move, just in case something goes wrong part way through the process.

Re: Differences...advantages mv vs. find

Richard Briggs — Wed, 27 Jun 2001 15:32:28 GMT

Well... I've done it both ways now.. and both work (from say /opt/dir [in lvolX in vg00] to /opt/dir2 [in lvolY in vg01 ] and actually... the first time I did the mv it did encounter an error, and the command exited...apparently, when mv encounters an error it doesn't delete the original data. For some reason, though, the find command makes me feel warmer and fuzzier. ;-)