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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This message is in MIME format and has been PGP signed. --=_7LPHxqkS6ZS0wef0ywo1nZa Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Quoting Matthew Ahrens via freebsd-fs <freebsd-fs@freebsd.org> (from=20=20 Tue,=204 Aug 2020 08:54:41 -0700): > This question was raised elsewhere, and I agree with this reply from Geor= ge > Wilson, my colleague and an expert in the i/o subsystems of ZFS as well a= s > 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 nev= er > 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 periodi= c > 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 hav= e > investigated similar concepts and one of our interns prototyped one of th= e > 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=20=20 any=20mention of the FreeBSD periodic scripts. There is nothing=20=20 mentioned=20and I think it would be good to mention the periodic=20=20 scrubbing=20functionality of FreeBSD in there (back then when I wrote=20=20 the=20scrubbing part for "periodic daily" I added docs to the=20=20 periodic.conf=20man-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=20=20 mention=20such kind of functionality (I think we should mention that as=20= =20 part=20of periodic daily there is the possibility to scrub and that more=20= =20 docs=20is available in periodic.conf (daily_scrub_zfs_* variables))? Bye, Alexander. --=20 http://www.Leidinger.net=20Alexander@Leidinger.net: PGP 0x8F31830F9F2772BF http://www.FreeBSD.org netchild@FreeBSD.org : PGP 0x8F31830F9F2772BF --=_7LPHxqkS6ZS0wef0ywo1nZa Content-Type: application/pgp-signature Content-Description: Digitale PGP-Signatur Content-Disposition: inline -----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----- --=_7LPHxqkS6ZS0wef0ywo1nZa--
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