On Thu, Dec 14, 2017 at 12:48 PM, O. Hartmann <ohartm...@walstatt.org> wrote: > Hello out there, > > I had to replace a HDD on a RAIDZ1 pool comprised from 4 HDDs, each 3 TB > (netto size of > the pool is about 8-9 TB, the used amount is reported to be ~ 6TB). > > I just started the rebuild/resilvering process and watch the pool crwaling at > ~ 18 MB/s. > At the moment, there is no load on the array, the host is a IvyBridge XEON > with 4 core/8 > threads and 3,4 GHz and 16 GB of RAM. The HDDs are attached to a on-board > SATA II (300 > MB/s max) Intel chip - this just for the record. > > Recently, I switch on the "sync" attribute on most of the defined pools's zfs > filesystems > - I also use a SSD for ZIL/L2ARC caching, but it seems to be unused recently > in FreeBSD > CURRENT's ZFS - this from a observers perspective only. > > When scrubbing, I see recently also reduced performance on the pool, so I'm > wondering > about the low throughput at the very moment when resilvering is in progress. > > If the "perspective" of "zpool status" is correct, then I have to wait after > two hours > for another 100 hours - ~ 4 days? Ups ... I think there is something badly > misconfigured > or missing. > > The pool is not "tuned" in any very sophisticated way, since I trust the > kernels ability > to scale automatically - if I'm not wrong for amd64 ... > > Are there any aspects to look at? > > Thanks in advance, > > Oliver > > -- > O. Hartmann > > Ich widerspreche der Nutzung oder Übermittlung meiner Daten für > Werbezwecke oder für die Markt- oder Meinungsforschung (§ 28 Abs. 4 BDSG).
This is kind of to be expected - for whatever reason, resilvers seem to go super slow at first and then speed up significantly. Just don't ask me how long "at first" is - I'd give it several (more) hours. I don't _think_ sync affects resilver speed (since that's a filesystem level setting and the resilver happens at the block level), but that's pure speculation. The Tuning guide at https://wiki.freebsd.org/ZFSTuningGuide also suggests a list of sysctls you can tweak, which could be worth a try: ### wiki If you're getting horrible performance during a scrub or resilver, the following sysctls can be set: vfs.zfs.scrub_delay=0 vfs.zfs.top_maxinflight=128 vfs.zfs.resilver_min_time_ms=5000 vfs.zfs.resilver_delay=0 Setting those sysctls to those values increased my (Shawn Webb's) resilver performance from 7MB/s to 230MB/s. ### -- Daniel Nebdal _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
