> From tom.sm...@wirelessconnect.eu Sat Feb 10 11:28:46 2018
> From: Tom Smyth <tom.sm...@wirelessconnect.eu>
> Date: Sat, 10 Feb 2018 09:10:30 +0000
> Subject: Re: For a FFS on an SSD, which of "-o" nil, "sync" &/ "softdep" is
> more data-safe and fast?
> To: mar...@martinbrandenburg.com
>
> Hi Martin... can you give a specific case where you have experienced
> negative impacts from thevmount options i suggested...
> It would be good to know...
Well I don't run noatime, so I can't give specific examples.
The point I was making is that noatime is a tradeoff. You give up
adherence to POSIX and historical Unix behavior in exchange for
performance and less disk wear.
Now I will admit that programs that rely on atime updates are few and
far between. It was always a bit niche. Nowadays, most software is
written on Linux, and most Linux systems use relatime.
It might be an acceptable tradeoff. To use the examples from the
manpage, if you know you're not going run any programs that need it and
that you'll never leave your laptop up for seven days or if you know
your news server doesn't need it, go ahead and disable it.
Just don't forget to consider it as a potential problem if you run into
trouble.
Here are some lines from /etc/daily. Without atime updates, it could
delete files. (Some of these might get more frequent mtime or ctime
updates which would bump the atime under noatime.)
The second set might be uncommented on a big multiuser system to clear
out /tmp since users don't. They might be a little irritated when the
file they've been reading for the last day gets deleted.
next_part "Removing scratch and junk files:"
if [ -d /tmp -a ! -L /tmp ]; then
cd /tmp && {
find -x . \
\( -path './ssh-*' -o -path ./.X11-unix -o -path ./.ICE-unix \
-o -path './tmux-*' \) \
-prune -o -type f -atime +7 -execdir rm -f -- {} \; 2>/dev/null
find -x . -type d -mtime +1 ! -path ./vi.recover ! -path ./.X11-unix \
! -path ./.ICE-unix ! -name . \
-execdir rmdir -- {} \; >/dev/null 2>&1; }
fi
# Additional junk directory cleanup would go like this:
#if [ -d /scratch -a ! -L /scratch ]; then
# cd /scratch && {
# find . ! -name . -atime +1 -execdir rm -f -- {} \;
# find . ! -name . -type d -mtime +1 -execdir rmdir -- {} \; \
# >/dev/null 2>&1; }
#fi
Martin
