hi, On Sat, Feb 21, 2026 at 9:30 PM Brad Spencer <[email protected]> wrote: > > Takashi YAMAMOTO <[email protected]> writes: > > > On Sat, Feb 21, 2026 at 9:34 AM Brad Spencer <[email protected]> wrote: > >> > >> Greg Troxel <[email protected]> writes: > >> > >> > Takashi YAMAMOTO <[email protected]> writes: > >> > > >> >> * is anyone using zfs in netbsd seriously? :-) > >> > > >> > I am using it on my desktop, and a on a dom0 hosting pkg builders. > >> > > >> > It mostly works, except that one must be careful not to simultaneously > >> > > >> > run low on memory > >> > run programs that dirty mmap'd pages (syncthing!) > >> > > >> > and probably also not > >> > > >> > run really low on memory such that there is a lot of paging > >> > > >> > >> This is a reaonsably summary of the quirks. > > > > what's the symptom of the issues? do you have PRs? > > The system will hang up, either very hard or just decay into a unusable > state. I reduced the maxvnodes is a very low value and that made it > sometimes possible to use ps and one will notice one or more processes > that are claiming that some form of memory isn't available, flt_noram5 > is pretty common, but not the only state I have seen. These processes > will not be killable. > > I don't think I created a PR specifically about what I see. kern/57558 > likely covers it, however. > > I trigger the situation by doing 3 or 4 parallel builds of the OS, > "build.sh -someargs -j2", one a DOMU with 2 vcpus and 16GB (it is > assumed that the system will page hard at times, which is fine). > However, even if I do only 1 build over and over (actually only 3 or 4 > times), the system will eventually put itself into the same state. > Something builds up over time or memory fragments in a manor that makes > it unusable, I suspect. The system is backed up using zfs snapshots and > even if I am not doing builds the system will decay into the same state, > but that tends to take a very long time (many months). The daily cron > jobs are mostly disabled as the ones that use find (hunting down core > files, etc) can hang up the system when they cross into the zfs > filesets, especially if they happen to run when a build it going on. > > Fairly easy to trigger, it just takes a while for everything to grind to > a halt so one has to be patience about it all.
didn't the last patch in PR/57558 improve the situation for you? when it happens, what are relevant threads (pgdaemon and others) doing? > > > Currently on a Xen DOMU PVH guest you can't get a kernel crash dump. so > that is a frustration point to figuring out what is happening. > > > (Been dealing with this for a long time, and a number of others know > about it) > > > > > > -- > Brad Spencer - [email protected] >
