Date: Wed, 22 Jul 2015 11:52:54 -0700 From: javocado <javocado@gmail.com> To: Gary Palmer <gpalmer@freebsd.org>, michelle@sorbs.net Cc: FreeBSD Filesystems <freebsd-fs@freebsd.org> Subject: Re: Prioritize resilvering priority Message-ID: <CAP1HOmT-qkOf6EuipPs26aNYTPC59_j6CNvK7tubM-HxVJCH-w@mail.gmail.com> In-Reply-To: <20150722003218.GD41419@in-addr.com> References: <CAP1HOmTo28BishnEdPCBsg7V4M4yYfcSKw_AmUbPP-mW4JtRQg@mail.gmail.com> <20150722003218.GD41419@in-addr.com>
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Thanks for all that feedback. Yes, this is for zfs. It looks like some of those sysctls are not available in 8.3: # sysctl vfs.zfs.scrub_delay sysctl: unknown oid 'vfs.zfs.scrub_delay' # sysctl vfs.zfs.resilver_delay sysctl: unknown oid 'vfs.zfs.resilver_delay' # sysctl vfs.zfs.zfs_top_maxinflight sysctl: unknown oid 'vfs.zfs.zfs_top_maxinflight' But I do have: vfs.zfs.vdev.max_pending: 10 (dynamic) vfs.zfs.scrub_limit: 10 (loader) So, I think I would want to lower one or both of these to increase I/O responsiveness on the system. Correct? How would the 2 play together in terms of which to adjust to achieve the best system performance at the expense of a longer resilver? On Tue, Jul 21, 2015 at 5:32 PM, Gary Palmer <gpalmer@freebsd.org> wrote: > On Tue, Jul 21, 2015 at 04:06:05PM -0700, javocado wrote: > > Hi, > > > > How does one go about prioritizing the resilvering process so it does not > > overwhelm normal disk I/O on a FreeBSD (8.3amd) system? Further, can > this > > be altered in real time, or do the settings have to be in place prior to > > the resilvering even starting? > > You don't state, but is this on ZFS? > > I assume they're on 8.3 also, but look at settings like > vfs.zfs.resilver_min_time_ms and vfs.zfs.resilver_delay in sysctl. > Searching for resilver_min_time_ms and resilver_delay may give > some hints, e.g. > > > http://broken.net/uncategorized/zfs-performance-tuning-for-scrubs-and-resilvers/ > > does the opposite to what you want, but it should give hints. Also > > > https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/zfs-advanced.html > > I think they're dynamic. I tuned the scrub settings and they took effect > immediately. > > Regards, > > Gary >
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