Michelle Sullivan http://www.mhix.org/ Sent from my iPad
> On 09 May 2019, at 22:50, Alan Somers <asom...@freebsd.org> wrote: > >> On Thu, May 9, 2019 at 5:37 AM Miroslav Lachman <000.f...@quip.cz> wrote: >> >> Dimitry Andric wrote on 2019/05/09 13:02: >>> On 9 May 2019, at 10:32, Miroslav Lachman <000.f...@quip.cz> wrote: >> >> [...] >> >>>> Disks are OK, monitored by smartmontools. There is nothing odd, just the >>>> long long scrubs. This machine was started with 4x 1TB (now 4x 4TB) and >>>> scrub was slow with 1TB disks too. This machine - HP ML110 G8) was my >>>> first machine with ZFS. If I remember it well it was FreeBSD 7.0, now >>>> running 11.2. Scrub was / is always about one week. (I tried some sysctl >>>> tuning without much gain) >>> >>> Unfortunately https://svnweb.freebsd.org/changeset/base/339034, which >>> greatly speeds up scrubs and resilvers, was not in 11.2 (since it was >>> cut at r334458). >>> >>> If you could update to a more recent snapshot, or try the upcoming 11.3 >>> prereleases, you will hopefully see much shorter scrub times. >> >> Thank you. I will try 11-STABLE / 11.3-PRERELEASE soon and let you know >> about the difference. >> >> Kind regards >> Miroslav Lachman > > On 11.3 and even much older releases, you can greatly speed up scrub > and resilver by tweaking some sysctls. If you have spinning rust, > raise vfs.zfs.top_maxinflight so they'll do fewer seeks. I used to > set it to 8192 on machines with 32GB of RAM. Raising > vfs.zfs.resilver_min_time_ms to 5000 helps a little, too. I tried this, but I found that whilst it could speed up the resilver (and scrubs) by as much as 25% it also had a performance hit were reads (particularly streaming video - which is what my server mostly did) would “pause” and “stutter” .. the balance came when I brought it back to around 200 * 15) . It would still stutter when running multiple streams (to the point of heavy load) but that was kinda expected... I tried to keep the load distributed off it and let the other front end servers stream and it seemed to result in a healthy balance. > > -Alan > _______________________________________________ > 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" _______________________________________________ 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"
