Date: Thu, 21 Dec 2017 22:48:02 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r327071 - stable/11/sbin/geom/class/mirror Message-ID: <201712212248.vBLMm2EG083366@repo.freebsd.org>
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Author: markj Date: Thu Dec 21 22:48:02 2017 New Revision: 327071 URL: https://svnweb.freebsd.org/changeset/base/327071 Log: MFC r326410: Document gmirror sysctls. Modified: stable/11/sbin/geom/class/mirror/gmirror.8 Directory Properties: stable/11/ (props changed) Modified: stable/11/sbin/geom/class/mirror/gmirror.8 ============================================================================== --- stable/11/sbin/geom/class/mirror/gmirror.8 Thu Dec 21 22:47:04 2017 (r327070) +++ stable/11/sbin/geom/class/mirror/gmirror.8 Thu Dec 21 22:48:02 2017 (r327071) @@ -24,7 +24,7 @@ .\" .\" $FreeBSD$ .\" -.Dd November 27, 2016 +.Dd November 30, 2017 .Dt GMIRROR 8 .Os .Sh NAME @@ -179,7 +179,7 @@ Defaults to 4096 bytes. Clear metadata on the given providers. .It Cm create Similar to -.Cm label, +.Cm label , but creates mirror without storing on-disk metadata in last sector. This special "manual" operation mode assumes some external control to manage mirror detection after reboot, device hot-plug and other external events. @@ -337,6 +337,45 @@ gmirror deactivate data da1 dd if=/dev/da1 of=/backup/data.img bs=1m gmirror activate data da1 .Ed +.Sh SYSCTL VARIABLES +The following +.Xr sysctl 8 +variables can be used to configure behavior for all mirrors. +.Bl -tag -width indent +.It Va kern.geom.mirror.debug +Control the verbosity of kernel logging related to mirrors. +A value larger than 0 will enable debug logging. +.It Va kern.geom.mirror.timeout +The amount of time, in seconds, to wait for all copies of a mirror to +appear before starting the mirror. +Disks that appear after the mirror has been started are not automatically +added to the mirror. +.It Va kern.geom.mirror.idletime +The amount of time, in seconds, which must elapse after the last write to +a mirror before that mirror is marked clean. +Clean mirrors do not need to be synchronized after a power failure or +system crash. +A small value may result in frequent overwrites of the disks' metadata +sectors, and thus may reduce the longevity of the disks. +.It Va kern.geom.mirror.disconnect_on_failure +Determine whether a disk is automatically removed from its mirror when an +I/O request to that disk fails. +.It Va kern.geom.mirror.sync_requests +The number of parallel I/O requests used while synchronizing a mirror. +This parameter may only be configured as a +.Xr loader.conf 5 +tunable. +.It Va kern.geom.mirror.sync_update_period +The period, in seconds, at which a synchronizing mirror's metadata is +updated. +Periodic updates are used to record a synchronization's progress so that +an interrupted synchronization may be resumed starting at the recorded +offset, rather than at the beginning. +A smaller value results in more accurate progress tracking, but also +increases the number of non-sequential writes to the disk being synchronized. +If the sysctl value is 0, no updates are performed until the synchronization +is complete. +.El .Sh NOTES Doing kernel dumps to .Nm @@ -382,6 +421,7 @@ there. .Xr mount 8 , .Xr newfs 8 , .Xr savecore 8 , +.Xr sysctl 8 , .Xr umount 8 .Sh HISTORY The @@ -394,7 +434,3 @@ utility appeared in There should be a way to change a component's priority inside a running mirror. .Pp There should be a section with an implementation description. -.Pp -Documentation for sysctls -.Va kern.geom.mirror.* -is missing.
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