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Document kern.geom.journal.* sysctls.

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PR:		docs/130548
Submitted by:	Hywel Mallett <hywel@hmallett.co.uk>
MFC after:	1 week
This commit is contained in:
pjd 2009-02-17 20:30:17 +00:00
parent a834b964e0
commit 566ae59e82
1 changed files with 102 additions and 6 deletions
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108
sbin/geom/class/journal/gjournal.8
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@ -1,4 +1,4 @@
.\" Copyright (c) 2006-2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
.\" Copyright (c) 2006-2009 Pawel Jakub Dawidek <pjd@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd April 13, 2008
.Dd February 17, 2008
.Dt GJOURNAL 8
.Os
.Sh NAME
@ -223,6 +223,106 @@ gjournal label da0s1d da0s1e && \e
mount -o async /dev/da0s1d.journal /mnt || \e
mount /dev/da0s1d /mnt
.Ed
.Sh SYSCTLS
Gjournal adds the sysctl level kern.geom.journal.
The string and integer information available is detailed below.
The changeable column shows whether a process with appropriate privilege may
change the value.
.Bl -column "accept_immediatelyXXXXXX" integerXXX -offset indent
.It Sy "sysctl name Type Changeable"
.It "debug integer yes"
.It "switch_time integer yes"
.It "force_switch integer yes"
.It "parallel_flushes integer yes"
.It "accept_immediately integer yes"
.It "parallel_copies integer yes"
.It "record_entries integer yes"
.It "optimize integer yes"
.El
.Pp
.Bl -tag -width 6n
.It Li debug
Setting a non-zero value enables debugging at various levels.
Debug level 1 will record actions at a journal level, relating to journal
switches, metadata updates etc.
Debug level 2 will record actions at a higher level, relating to the numbers of
entries in journals, access requests etc.
Debug level 3 will record verbose detail, including insertion of I/Os to the
journal.
.It Li switch_time
The maximum number of seconds a journal is allowed to remain open before
switching to a new journal.
.It Li force_switch
Force a journal switch when the journal uses more than N% of the free journal space.
.It Li parallel_flushes
The number of flush I/O requests to be sent in parallel when flushing the journal to the data provider.
.It Li accept_immediately
The maximum number of I/O requests accepted at the same time.
.It Li parallel_copies
The number of copy I/O requests to send in parallel.
.It Li record_entries
The maximum number of record entries to allow in a single journal.
.It Li optimize
Controls whether entries in a journal will be optimized, by combining overlapping I/Os into a single I/O, and reordering the entries in a journal. This can be disabled by setting the sysctl to 0.
.El
.Ss cache
The string and integer information available for the cache level
is detailed below.
The changeable column shows whether a process with appropriate
privilege may change the value.
.Bl -column "alloc_failuresXXXXXX" integerXXX -offset indent
.It Sy "sysctl name Type Changeable"
.It "used integer no"
.It "limit integer yes"
.It "divisor integer no"
.It "switch integer yes"
.It "misses integer yes"
.It "alloc_failures integer yes"
.El
.Pp
.Bl -tag -width 6n
.It Li used
The number of bytes currently allocated to the cache.
.It Li limit
The maximum number of bytes to be allocated to the cache.
.It Li divisor
Sets the cache size to be used as a proportion of kmem_size. A value of 2 (the default) will cause the cache size to be set to 1/2 of the kmem_size.
.It Li switch
Force a journal switch when this percentage of cache has been used.
.It Li misses
The number of cache misses, when data has been read, but was not found in the cache.
.It Li alloc_failures
The number of times memory failed to be allocated to the cache because the cache limit was hit.
.El
.Ss stats
The string and integer information available for the statistics level
is detailed below.
The changeable column shows whether a process with appropriate
privilege may change the value.
.Bl -column "skipped_bytesXXXXXX" integerXXX -offset indent
.It Sy "sysctl name Type Changeable"
.It "skipped_bytes integer yes"
.It "combined_ios integer yes"
.It "switches integer yes"
.It "wait_for_copy integer yes"
.It "journal_full integer yes"
.It "low_mem integer yes"
.El
.Pp
.Bl -tag -width 6n
.It Li skipped_bytes
The number of bytes skipped.
.It Li combined_ios
The number of I/Os which were combined by journal optimization.
.It Li switches
The number of journal switches.
.It Li wait_for_copy
The number of times the journal switch process had to wait for the previous journal copy to complete.
.It Li journal_full
The number of times the journal was almost full, forcing a journal switch.
.It Li low_mem
The number of times the low_mem hook was called.
.El
.Sh SEE ALSO
.Xr geom 4 ,
.Xr geom 8 ,
@ -237,7 +337,3 @@ utility appeared in
.Fx 7.0 .
.Sh AUTHORS
.An Pawel Jakub Dawidek Aq pjd@FreeBSD.org
.Sh BUGS
Documentation for sysctls
.Va kern.geom.journal.*
is missing.