On Fri, Jul 15, 2022 at 11:07 PM Greg Wooledge <g...@wooledge.org> wrote:
> On Sat, Jul 16, 2022 at 03:49:09AM +0100, Gareth Evans wrote: > > $ sudo crontab -l > > [...] > > @reboot for f in $(/usr/sbin/zfs list -t snap -o name|grep reboot); do > /usr/sbin/zfs destroy $f;done > > @reboot /usr/sbin/zfs snap -r rpool@reboot > > > > > > Prepending "/usr/sbin/" to "zfs" doesn't make a difference. > > Let me start by saying I don't know a single thing about ZFS. > > My first reaction to this thread of yours is, "Well, read the email that > cron sends you and see what the errors are." > > But that's the easy and obvious reaction. My second reaction goes a > little bit deeper: > > "All your crontab entries run in parallel. So your first line which > has zfs in it, and your second line which also has zfs in it, those both > run at the same time. Is that OK?" > > Since I have no idea what any of those ZFS commands do, I can't tell > whether it's OK to have that race condition. I suspect it's not OK, > but what do I know? > > My third reaction goes something like this: > > "If you wanted to run a bunch of commands a boot time, without setting > up systemd units for them, and proper dependencies, why didn't you just > use /etc/rc.local?" > rc.local does not exist in Debian 11. "/etc/rc.local: No such file or directory" should it be a file or a directory? > Using a crontab to duplicate the functionality of rc.local seems odd to me. > > Anyway, read your errors. They may tell you what's wrong. Figure out > whether your commands are allowed to run in parallel. If they're not, > use a *script*, instead of a bunch of parallel commands. That script > could be /etc/rc.local, or it could be a separate script that you call > from rc.local, or even call from crontab if you really insist. > > -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ Debian - The universal operating system ⢿⡄⠘⠷⠚⠋⠀ https://www.debian.org/ ⠈⠳⣄⠀⠀
