Re: mount -t null -o noatime

[David Holland <dholland-tech%netbsd.org@localhost>]

On Mon, Dec 23, 2024 at 12:47:50PM +0100, Edgar Fu? wrote:
 > Suppose I have a (FFS) fs mounted with atime (e.g., without -o noatime) 
 > and I null-mount that fs somewhere else with -o noatime.
 > Will that do what I expect, e.g. will operations on the null-mounted fs 
 > leave the on-disc atimes alone?

That's an excellent question. I would say that it should, but whether
it _does_ is anyone's guess. If you try it, let us know :-)

 > The use case I have in mind is restoring from a backup; updating the atimes 
 > of the directories would be a waste of time since the backup program will 
 > restore them afterwards anyway.  Or is there an easier way for this?

Enabling wapbl for the undump (if you otherwise don't) will probably
get you 95% of the win (over traditional) without taking any real
work.

You might also undump with -oasync on the grounds that if the cat
pulls out the power while you're doing it you can just newfs and start
over. Although that depends on what/how much you're restoring.

-- 
David A. Holland
dholland%netbsd.org@localhost