Date: Sat, 15 Aug 2020 12:47:23 +0200 From: Alexander Leidinger <Alexander@leidinger.net> To: freebsd-fs@freebsd.org Subject: Re: zfs scrub enable by default Message-ID: <20200815124723.Horde.XErLXGD767bCee6vNVm5gBT@webmail.leidinger.net> In-Reply-To: <CAJjvXiEXEdAFXpXkGvt4fymA17kNdp6XkZV5taGKLoP2GvMHbw@mail.gmail.com> References: <cca34d1a-1892-41ec-ce45-84865100c6e1@FreeBSD.org> <CAJjvXiEXEdAFXpXkGvt4fymA17kNdp6XkZV5taGKLoP2GvMHbw@mail.gmail.com>
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[-- Attachment #1 --] Quoting Matthew Ahrens via freebsd-fs <freebsd-fs@freebsd.org> (from Tue, 4 Aug 2020 08:54:41 -0700): > This question was raised elsewhere, and I agree with this reply from George > Wilson, my colleague and an expert in the i/o subsystems of ZFS as well as > having lots of experience with customers: > > Having scrubs enabled by default is a great idea but at Sun (and Delphix > too) we found that the impact was often too much for some > workloads/customers. This is the challenge we faced and why there was never > a policy to enable it everywhere. We did explore ideas to make the impact > less and to be able to always scrub. Some of those ideas included periodic > or continuous scrubs where the impact could be reduced by only scrubbing > portions of the pool at a time, at a reduced i/o rate. At Delphix, we have > investigated similar concepts and one of our interns prototyped one of the > ideas.Much has changed since the early scrub days and revisiting some of > the earlier ideas and investigating new ones is probably a good topic for > the community. I do think that just enabling scrub by default without > further enhancements would still be too impactful for some customers but > the concept definitely has merit. Does the zpool man-page come from OpenZFS, or is it a FreeBSD addition? The reason for this question is, that I had checked the content for any mention of the FreeBSD periodic scripts. There is nothing mentioned and I think it would be good to mention the periodic scrubbing functionality of FreeBSD in there (back then when I wrote the scrubbing part for "periodic daily" I added docs to the periodic.conf man-page, but failed to mention it in the zpool man-page). If the zpool man-page comes from OpenZFS, what would be a good way to mention such kind of functionality (I think we should mention that as part of periodic daily there is the possibility to scrub and that more docs is available in periodic.conf (daily_scrub_zfs_* variables))? Bye, Alexander. -- http://www.Leidinger.net Alexander@Leidinger.net: PGP 0x8F31830F9F2772BF http://www.FreeBSD.org netchild@FreeBSD.org : PGP 0x8F31830F9F2772BF [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJfN706AAoJEBINsJsD+NiGyngP/33EDD8FrsnYqs7OYmwOFKRt 9mShRR/zOeAOwYVP+W7bZpnzyOjh2y83vGOX3QgAYVXnqaxm4/p/FKtvPf4aeYXI sgcX/Z/zAQzWTPZLZtqrdW/Lbrgmcsr9l7NhklVHwHLxd5+OXusAEbGF3kycRLvV 5Yt6T+PmBMcvtcUvJ9MDfFEe++xP2cPHYtKZe2sH8auiJ7mCXLZmCLvFbTUWHi6x DKqNw9so6yb5ZADbI2PenwTZ4rCpwPeujtWIwh4Snn9XRjYHoK792W8eemo74Mgn nRCTO+xWIn8XqKPBzKel49FVsJEDd4EPEUayxOQcPomvkyp8vJBM0Xv4xhAOpSjh PKi+0O+P8BaF5dyAZu2k6GQQJq40ScJ8ygWt6qMle9kSLuk+yRCwA3bCofFqfcKn qyqj20z94/AblCLajcxwf9ZAZyOZrkCo7sMvqdHRool59fzb/SMeQgu93ZflcdFV ZpRqErsgsklxlNs4uiYMzrGkhY5KO1cji2+Pn7IxhVXO73biMR/d4V650+9/tRKv ZA2ME9LRVSV6qxDrHQGd/GT2ofJLnvzPgrb4yk4ru0uxfx8Fmrv0mh9VuTG2NYJ/ YiKuxUJZR+/xvIcEQijnPuFnU+q0dbwn2ZctGP2smkI/2KZgWZEiV5GdNgj11+cJ +a2ISR1IcDDJuHl6bjoH =Htzy -----END PGP SIGNATURE-----home | help
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