Am 09.09.20 um 00:45 schrieb Graham Perrin:
On 08/09/2020 08:43, Stefan Esser wrote:OpenZFS seems to work quite well for me, in general, but I have questions regarding the L2ARC statistics.…The sysutils/zfs-stats port reports the following values for this system, BTW: ------------------------------------------------------------------------ ZFS Subsystem Report Tue Sep 8 09:02:46 2020 ------------------------------------------------------------------------…Quite a number of sysctl variable names have changed, and the port needs to be adapted to the new names (therefore there are lots of 0 values in the -L output). The following names used by zfs-stats do not exist in OpenZFS: kstat.zfs.misc.arcstats.recycle_miss kstat.zfs.misc.arcstats.l2_write_buffer_bytes_scanned kstat.zfs.misc.arcstats.l2_write_buffer_iter kstat.zfs.misc.arcstats.l2_write_buffer_list_iter kstat.zfs.misc.arcstats.l2_write_buffer_list_null_iter kstat.zfs.misc.arcstats.l2_write_full kstat.zfs.misc.arcstats.l2_write_in_l2 kstat.zfs.misc.arcstats.l2_write_io_in_progress kstat.zfs.misc.arcstats.l2_write_not_cacheable kstat.zfs.misc.arcstats.l2_write_passed_headroom kstat.zfs.misc.arcstats.l2_write_pios kstat.zfs.misc.arcstats.l2_write_spa_mismatch kstat.zfs.misc.arcstats.l2_write_trylock_fail kstat.zfs.misc.arcstats.l2_writes_hdr_miss vfs.zfs.vdev.cache.size The existence of vfs.zfs.vdev.cache.size vs vfs.zfs.vdev.cache_size can be used to detect OpenZFS, and is easily fixed. But the above listed L2ARC values seem to have been removed from or have never existed in OpenZFS, and I did not find any substitutes. Are there any plans to re-create them in OpenZFS on FreeBSD or are they gone for good?Recalling <https://lists.freebsd.org/pipermail/freebsd-current/2020-March/075661.html>, on 28/03/2020 15:17,28/03/2020 15:17, Allan Jude wrote:>> … >> >> Basically 'arc' was converted to a subtree. >> >> We should add some backwards compat sysctls to cover some of >> these renames etc so configs and scripts don't break etc.
This is not possible for quite a number of sysctls, since there is no simple 1:1 mapping for many of them. And there is an annoyance that I had noticed before but now have tracked down: $ time sysctl kstat.zfs.misc.dbufs | wc 55327 2047031 16333472 real 0m16,446s user 0m0,055s sys 0m16,397s Somebody decided to put a complete list of dbufs under this sysctl and thus querying "kstat.zfs.misc" takes that long (16 seconds to generate 16 MB of output on my system), even if only a few other values in "kstat.zfs.misc" are needed. I do not know whether there is any chance to get that debug output moved out of the "misc", e.g. into a new "debug" sub-tree. I'm afraid, that on Linux there are scripts that expect it under this name. If it is not acceptable to the upstream, we should locally modify the sysctl tree to move that variable out of "misc", IMHO. (While not taking much time, "kstat.zfs.misc.dbgmsg" should also be relocted to a "debug" sub-tree, IMHO ...) zfs-stats needs tens of values from "misc", and if they are not all added individually to the Kstat array, this will limit the response time to any zfs-stats invocation. It is not too hard to add the new variables in zfs-stats and to adapt the calculations to derive meaningful values to display. But if it always takes 16 seconds to generate any output, I'm not likely to use it too often ... Regards, STefan
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