On Tue, Jun 4, 2019 at 3:34 PM Mogens Jensen <mogens-jen...@protonmail.com> wrote:
> Can anyone with experience running OpenBSD routers without UPS, tell if > filesystem corruption is going to be a problem after power outages, or > if there are any officially supported ways to make the system resilient > enough to not break after a power outage? > > I'm using an mSATA disk with MLC flash in the router. > I have some OpenBSD routers without UPS protection (Soekris net6501 devices) and after using them for some years, I think it's not possible to have absolute 100% protection from filesystem corruption due to power problems, without causing other problems such as making the system overly fragile to upgrade or maintain. However, it works reasonably well to put /var/log on an MFS file system, and set up a cron job (as well as a line in /etc/rc.shutdown) to periodically rsync /var/log to another directory (so that logs will be preserved after a reboot). This works fairly well, and the system comes up properly after power failures easily over 98% of the time. Very rarely (i.e. I have seen it happen twice in a decade) you will get unlucky and have corruption anyway that requires you to run "fsck -y" manually. This is rare enough that I haven't bothered trying to automate it away. To accomplish this, I installed OpenBSD with /var/log being a separate filesystem, then edited /etc/fstab to rename /var/log to /mfs/log, and add a new entry for /var/log: swap /var/log mfs rw,nodev,nosuid,-s=128M,-P=/mfs/log 0 0 Initializing the MFS /var/log by loading from /mfs/log, combined with an rsync command in /etc/rc.shutdown, is what gives the illusion of /var/log being preserved across reboots. -ken
