Date: Tue, 18 Nov 2014 14:43:57 -0800 From: Matthew Ahrens <matt@mahrens.org> To: Slawa Olhovchenkov <slw@zxy.spb.ru> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, "src-committers@freebsd.org" <src-committers@freebsd.org>, Xin LI <delphij@freebsd.org> Subject: Re: svn commit: r274673 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <CAKUb7ivWXvqtFXNig5ku9Bn7fwWo1g=%2B4_QoHh%2BbwyocHbvOaA@mail.gmail.com> In-Reply-To: <20141118220030.GA31347@zxy.spb.ru> References: <201411181840.sAIIe2C7094558@svn.freebsd.org> <20141118220030.GA31347@zxy.spb.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, Nov 18, 2014 at 2:00 PM, Slawa Olhovchenkov <slw@zxy.spb.ru> wrote: > On Tue, Nov 18, 2014 at 06:40:02PM +0000, Xin LI wrote: > > > Author: delphij > > Date: Tue Nov 18 18:40:01 2014 > > New Revision: 274673 > > URL: https://svnweb.freebsd.org/changeset/base/274673 > > > > Log: > > Allow tuning zfs_max_recordsize via loader tunable. Tuning is NOT > > recommended. > > This is not tuning, this is simple guard. > And can be safe changed (incrased, at the least) in any time. > For some workload optimal is maximum, i.e. 16MB. > May be better comment: increasing this value required strong > understaning after-effects of increasing memory consumption and > bulk data transfers. (sorry for english) > I agree -- setting recordsize to 16MB is an easy way to make performance suck if you don't know what you're doing. But it isn't dangerous from a correctness point of view. --matt > > > Requested by: Slawa Olhovchenkov <slw zxy spb ru> > > MFC after: 2 weeks > > Thanks, can you allow RW? > > > Modified: > > head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c > > > > Modified: > head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c > > > ============================================================================== > > --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c > Tue Nov 18 18:03:40 2014 (r274672) > > +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c > Tue Nov 18 18:40:01 2014 (r274673) > > @@ -51,6 +51,8 @@ > > #include <sys/dsl_userhold.h> > > #include <sys/dsl_bookmark.h> > > > > +SYSCTL_DECL(_vfs_zfs); > > + > > /* > > * The SPA supports block sizes up to 16MB. However, very large blocks > > * can have an impact on i/o latency (e.g. tying up a spinning disk for > > @@ -61,6 +63,9 @@ > > * of this setting. > > */ > > int zfs_max_recordsize = 1 * 1024 * 1024; > > +SYSCTL_INT(_vfs_zfs, OID_AUTO, max_recordsize, CTLFLAG_RDTUN, > > + &zfs_max_recordsize, 0, > > + "Maximum block size. Expect dragons when tuning this."); > > > > #define SWITCH64(x, y) \ > > { \ > > _______________________________________________ > > svn-src-all@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/svn-src-all > > To unsubscribe, send any mail to "svn-src-all-unsubscribe@freebsd.org" > >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAKUb7ivWXvqtFXNig5ku9Bn7fwWo1g=%2B4_QoHh%2BbwyocHbvOaA>