Re: Swapping from a zvol results in a deadman panic
"Matthew X. Economou"wrote: > My FreeBSD 10.3-RELEASE-p16 server crashes in the middle of a Poudriere > bulk run (see below). This crash happens even if I lower > vfs.zfs.arc_max or tweak vm.v_free_min/target/reserved/severe. I'm > looking for configuration advice in case I missed something obvious, > since this seems to work on Illumos- and Linux-derived O/Ses, but > failing that, I'd like to get some advice as to how to go about > debugging this. I doubt the deadman timer causes the system to stop > responding. It's more likely a race condition elsewhere. > > The pool itself uses 4k sectors and is geli-encrypted. I configured the > swap zvol based on root-on-ZFS install instructions found in the FreeBSD > wiki: Paging on geli-encrypted devices is known to cause deadlocks on FreeBSD, even if ZFS isn't involved directly: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=209759 Adding ZFS to the mix is unlikely to help ... > zfs create -V 6G -o org.freebsd:swap=on -o checksum=off -o > compression=off -o dedup=off -o sync=disabled -o primarycache=none > zroot/swap > > The ZoL wiki recommends a slightly different zvol configuration: > > zfs create -V 4G -b $(getconf PAGESIZE) -o logbias=throughput -o > sync=always -o primarycache=metadata -o com.sun:auto-snapshot=false > rpool/swap > > I'm not sure how much of this applies to FreeBSD due to differences in > kernel design/implementation. Does anyone have an idea of what might be > going on and how I might get this working? You could try the patch from the PR and enable the kern.geom.eli.use_uma_for_all_writes sysctl. If you have a core dump, you may want to confirm that the g_eli_worker is waiting for memory first. Fabian pgp_dI3TEXEPz.pgp Description: OpenPGP digital signature
Swapping from a zvol results in a deadman panic
On Sat, 4 Feb 2017 08:18:28 -0500 "Matthew X. Economou"wrote: >My FreeBSD 10.3-RELEASE-p16 server crashes in the middle of a Poudriere >bulk run (see below). This crash happens even if I lower >vfs.zfs.arc_max or tweak vm.v_free_min/target/reserved/severe. I'm >looking for configuration advice in case I missed something obvious, >since this seems to work on Illumos- and Linux-derived O/Ses, but >failing that, I'd like to get some advice as to how to go about >debugging this. I doubt the deadman timer causes the system to stop >responding. It's more likely a race condition elsewhere. > Those who try to create deadlocks should not complain when they succeed. Sigh. Scott Bennett, Comm. ASMELG, CFIAG ** * Internet: bennett at sdf.org *xor* bennett at freeshell.org * ** * "A well regulated and disciplined militia, is at all times a good * * objection to the introduction of that bane of all free governments * * -- a standing army." * *-- Gov. John Hancock, New York Journal, 28 January 1790 * ** ___ freebsd-stable@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"