Date: Thu, 21 Apr 2022 15:44:02 +0200 From: Alexander Leidinger <Alexander@leidinger.net> To: Mateusz Guzik <mjguzik@gmail.com> Cc: Doug Ambrisko <ambrisko@ambrisko.com>, freebsd-current@freebsd.org Subject: Re: nullfs and ZFS issues Message-ID: <20220421154402.Horde.I6m2Om_fxqMtDMUqpiZAxtP@webmail.leidinger.net> In-Reply-To: <CAGudoHEyCK4kWuJybD4jzCHbGAw46CQkPx_yrPpmRJg3m10sdQ@mail.gmail.com> References: <Yl31Frx6HyLVl4tE@ambrisko.com> <20220420113944.Horde.5qBL80-ikDLIWDIFVJ4VgzX@webmail.leidinger.net> <YmAy0ZNZv9Cqs7X%2B@ambrisko.com> <20220421083310.Horde.r7YT8777_AvGU_6GO1cC90G@webmail.leidinger.net> <CAGudoHEyCK4kWuJybD4jzCHbGAw46CQkPx_yrPpmRJg3m10sdQ@mail.gmail.com>
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This message is in MIME format and has been PGP signed. --=_mCoQQKdVyX4TDmpIgE_NwAt Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Quoting Mateusz Guzik <mjguzik@gmail.com> (from Thu, 21 Apr 2022=20=20 14:50:42=20+0200): > On 4/21/22, Alexander Leidinger <Alexander@leidinger.net> wrote: >> I tried nocache on a system with a lot of jails which use nullfs, >> which showed very slow behavior in the daily periodic runs (12h runs >> in the night after boot, 24h or more in subsequent nights). Now the >> first nightly run after boot was finished after 4h. >> >> What is the benefit of not disabling the cache in nullfs? I would >> expect zfs (or ufs) to cache the (meta)data anyway. >> > > does the poor performance show up with > https://people.freebsd.org/~mjg/vnlru_free_pick.diff ? I would like to have all the 22 jails run the periodic scripts a=20=20 second=20night in a row before trying this. > if the long runs are still there, can you get some profiling from it? > sysctl -a before and after would be a start. > > My guess is that you are the vnode limit and bumping into the 1 second sl= eep. That would explain the behavior I see since I added the last jail=20=20 which=20seems to have crossed a threshold which triggers the slow=20=20 behavior. Current=20status (with the 112 nullfs mounts with nocache): kern.maxvnodes: 10485760 kern.numvnodes: 3791064 kern.freevnodes: 3613694 kern.cache.stats.heldvnodes: 151707 kern.vnodes_created: 260288639 The maxvnodes value is already increased by 10 times compared to the=20=20 default=20value on this system. Bye, Alexander. --=20 http://www.Leidinger.net=20Alexander@Leidinger.net: PGP 0x8F31830F9F2772BF http://www.FreeBSD.org netchild@FreeBSD.org : PGP 0x8F31830F9F2772BF --=_mCoQQKdVyX4TDmpIgE_NwAt Content-Type: application/pgp-signature Content-Description: Digitale PGP-Signatur Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIzBAABCAAdFiEER9UlYXp1PSd08nWXEg2wmwP42IYFAmJhX6IACgkQEg2wmwP4 2IZTeA//cJhz26bByMcB3GGJiE1hbe/vkBg5GmXXecD5mD6BSDbBoMM3lA5IW/v5 a9JDus3iY+oeAhyJO5ig5znRwVkfpOhHbO9dFqIdp6mwIN1k2+91AMr6SMTEHhnu cvlLVUnlhZeSLzW4ty79iKsLYXyheC06MMrHVawrJs/i22XOS4+zPyT33N/WNMLs UGNqWFuyYw5+PQCGcX46NSbEZYiDLN9AMM9lXwY2RnY8ziX5JnW6lEU88OrW7O/v F5Y2uDj1UPsmkPwsaVtblDpzpcI/bEoR2/YECSjX07kVJ/r5cLI9FMbAxBn4Nbyb mKpYYYX+ORzmS9uKML/pZJUsATCM552AALU8LLtbUyZ2V09uOo3nsICdDbB8CAvi A/E9acuGqQFbHE/iXQrU+U01GmRrb9A+OG7oYMHmMqQccmi5hDYWzXpGzrU/8jGU J2q/32chB2czyYg9QT0U4KVKuxE2Gpn2Vxl60A1EmrLTtnbsbMugJIQOr2fpekYo 1BoFdqyUpfL5VP+GuPiTzCPikLWEAFk4v1wVpdd6vd0MMXcghyTZ9hXoWTAYW80V xnSpT92sI/VoMyjcTjPAwevvdfbSKtSPOg2WKa3/XTJUKCn0m+x2LQwTydjO+olp NP63zlpAwuIQzg46pNdX3PYCy+418Dwb0vh9JkoHKgPxfWsxe/0= =OibP -----END PGP SIGNATURE----- --=_mCoQQKdVyX4TDmpIgE_NwAt--
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