HAMMER2 emergency space mode

As anyone who has been running HAMMER1 or HAMMER2 has noticed, snapshots and copy on write and infinite history can eat a lot of disk space, even if the actual file volume isn’t changing much.  There’s now an ‘emergency mode‘ for HAMMER2, where disk operations can happen even if there isn’t space for the normal history activity.  It’s dangerous, in that the normal protections against data loss if power is cut go away, and snapshots created while in this mode will be mangled.  So definitely don’t leave it on!

utmp out, utmpx in

The headline is a little misleading; umtpx has been in DragonFly forever, but now utmp is really retired and programs adjusted to match.  The change is not that user-affecting and utmp data is still accessible; this is part of the ABI change alluded to over the past week.

If you are not familiar with utmp(5) and utmpx(5), they are databases in /var that track user logins and system restarts.  utmpx is of course better cause it has an X.