[lvm-devel] [PATCH 30/35] Add --vgmetadatacopies to vgcreate man page, command, and lvm.conf.
Dave Wysochanski
dwysocha at redhat.com
Tue Jun 22 03:06:03 UTC 2010
Allow parsing of --vgmetadatacopies for vgcreate. Accept
--metadatacopies as a synonym for --vgmetadatacopies. Other
patches will add balancing algorithm before the metadata is
written in vg_write().
Signed-off-by: Dave Wysochanski <dwysocha at redhat.com>
---
man/lvm.conf.5.in | 23 +++++++++++++++++++++++
man/vgcreate.8.in | 15 +++++++++++++++
tools/commands.h | 5 +++--
tools/toollib.c | 12 ++++++++++++
tools/vgcreate.c | 8 ++------
5 files changed, 55 insertions(+), 8 deletions(-)
diff --git a/man/lvm.conf.5.in b/man/lvm.conf.5.in
index 02ebb2a..ff0c35e 100644
--- a/man/lvm.conf.5.in
+++ b/man/lvm.conf.5.in
@@ -406,6 +406,29 @@ The metadata areas are treated as circular buffers, so
unused space becomes filled with an archive of the most recent
previous versions of the metadata.
.IP
+\fBvgmetadatacopies\fP \(em When creating a volume group using the
+LVM2 metadata format, this is the default number of copies of metadata
+desired across all the physical volumes in the volume group. If set to
+a non-zero value, LVM will attempt to balance metadata areas across
+the physical volumes in the volume group to achieve the number
+of metadata copies specified. LVM implements the balancing through
+automatically setting and clearing metadata ignore
+(See \fBpvchange --metadataignore\fP) on physical volumes created with
+a non-zero value of \fBpvmetadatacopies\fP. Balancing may be triggered
+by an LVM command that adds or removes physical volumes (\fBvgextend\fP
+or \fBvgreduce\fP, \fBvgsplit\fP, \fBvgmerge\fP), when physical
+volumes go missing or reappear, or when a new value is explicity set
+(See \fBvgchange --vgmetadatacopies\fP).
+Setting \fBvgmetadatacopies\fP to 0 disables metadata balancing. It
+is not an error to set a value larger than the sum of all metadata areas
+on all physical volumes. The value can be overridden on the command line
+with \fB--vgmetadatacopies\fP. This option may be useful for volume groups
+containing large numbers of physical volumes. It offers a simple way
+to specify a reasonable number of metadata copies (for example 5) without
+having to know ahead of time which physical volumes should have metadata.
+Having a smaller number of metadata areas offers better performance
+than the default of reading and writing metadata on all physical volumes.
+.IP
\fBdirs\fP \(em List of directories holding live copies of LVM2
metadata as text files. These directories must not be on logical
volumes. It is possible to use LVM2 with a couple of directories
diff --git a/man/vgcreate.8.in b/man/vgcreate.8.in
index 24d1642..2c8ce34 100644
--- a/man/vgcreate.8.in
+++ b/man/vgcreate.8.in
@@ -16,6 +16,8 @@ vgcreate \- create a volume group
.RB [ -M | \-\-metadatatype type]
.RB [ -p | \-\-maxphysicalvolumes
.IR MaxPhysicalVolumes ]
+.RB [ \-\-[vg]metadatacopies ]
+.IR copies ]
.RB [ \-s | \-\-physicalextentsize
.IR PhysicalExtentSize [ \fBbBsSkKmMgGtTpPeE\fR ]]
.RB [ \-t | \-\-test ]
@@ -74,6 +76,19 @@ for tool performance reasons, you should consider
some use of \fB--pvmetadatacopies 0\fP
as described in \fBpvcreate(8)\fP.
.TP
+.BR \-\-vgmetadatacopies " " \fI#copies\fR
+Sets the targetted number of metadata copies in the volume group.
+If set to a non-zero value, LVM will attempt to use \fB#copies\fP to
+determine the set of physical volumes on which to read and write metadata.
+LVM manages the set automatically by setting or clearing the 'metadataignore'
+flag on the physical volumes (see \fBpvchange\fP), and in this way balances
+metadata across PVs in the volume group. Only physical volumes created
+with a non-zero value of \fBmetadatacopies\fP are used in the set of physical
+volumes. This option is useful for volume groups containing large numbers
+of physical volumes containing metadata as it may be used to minimize metadata
+read and write overhead.
+The default value is 0, which disables LVM metadata balancing.
+.TP
.BR \-s ", " \-\-physicalextentsize " " \fIPhysicalExtentSize\fR[\fBbBsSkKmMgGtTpPeE\fR]
Sets the physical extent size on physical volumes of this volume group.
A size suffix (k for kilobytes up to t for terabytes) is optional, megabytes
diff --git a/tools/commands.h b/tools/commands.h
index 62a684b..8f5ff3a 100644
--- a/tools/commands.h
+++ b/tools/commands.h
@@ -776,6 +776,7 @@ xx(vgcreate,
"\t[-h|--help]" "\n"
"\t[-l|--maxlogicalvolumes MaxLogicalVolumes]" "\n"
"\t[-M|--metadatatype 1|2] " "\n"
+ "\t[--[vg]metadatacopies #copies] " "\n"
"\t[-p|--maxphysicalvolumes MaxPhysicalVolumes] " "\n"
"\t[-s|--physicalextentsize PhysicalExtentSize[bBsSkKmMgGtTpPeE]] " "\n"
"\t[-t|--test] " "\n"
@@ -787,8 +788,8 @@ xx(vgcreate,
addtag_ARG, alloc_ARG, autobackup_ARG, clustered_ARG, maxlogicalvolumes_ARG,
maxphysicalvolumes_ARG, metadatatype_ARG, physicalextentsize_ARG, test_ARG,
force_ARG, yes_ARG, zero_ARG, labelsector_ARG, metadatasize_ARG,
- pvmetadatacopies_ARG, metadatacopies_ARG, dataalignment_ARG,
- dataalignmentoffset_ARG)
+ pvmetadatacopies_ARG, metadatacopies_ARG, vgmetadatacopies_ARG,
+ dataalignment_ARG, dataalignmentoffset_ARG)
xx(vgdisplay,
"Display volume group information",
diff --git a/tools/toollib.c b/tools/toollib.c
index 02b06fd..e56a3e5 100644
--- a/tools/toollib.c
+++ b/tools/toollib.c
@@ -1243,6 +1243,18 @@ int vgcreate_params_set_from_args(struct cmd_context *cmd,
return 1;
}
+ if (arg_count(cmd, metadatacopies_ARG)) {
+ vp_new->metadata_copies = arg_int_value(cmd, metadatacopies_ARG,
+ DEFAULT_VGMETADATACOPIES);
+ } else if (arg_count(cmd, vgmetadatacopies_ARG)) {
+ vp_new->metadata_copies = arg_int_value(cmd, vgmetadatacopies_ARG,
+ DEFAULT_VGMETADATACOPIES);
+ } else {
+ vp_new->metadata_copies = find_config_tree_int(cmd,
+ "metadata/vgmetadatacopies",
+ DEFAULT_VGMETADATACOPIES);
+ }
+
return 0;
}
diff --git a/tools/vgcreate.c b/tools/vgcreate.c
index 6087145..3bb500f 100644
--- a/tools/vgcreate.c
+++ b/tools/vgcreate.c
@@ -35,11 +35,6 @@ int vgcreate(struct cmd_context *cmd, int argc, char **argv)
argc--;
argv++;
- if (arg_count(cmd, metadatacopies_ARG)) {
- log_error("Invalid option --metadatacopies, "
- "use --pvmetadatacopies instead.");
- return EINVALID_CMD_LINE;
- }
pvcreate_params_set_defaults(&pp);
if (!pvcreate_params_validate(cmd, argc, argv, &pp)) {
return EINVALID_CMD_LINE;
@@ -68,7 +63,8 @@ int vgcreate(struct cmd_context *cmd, int argc, char **argv)
!vg_set_max_lv(vg, vp_new.max_lv) ||
!vg_set_max_pv(vg, vp_new.max_pv) ||
!vg_set_alloc_policy(vg, vp_new.alloc) ||
- !vg_set_clustered(vg, vp_new.clustered))
+ !vg_set_clustered(vg, vp_new.clustered) ||
+ !vg_set_mda_copies(vg, vp_new.metadata_copies))
goto bad_orphan;
if (!lock_vol(cmd, VG_ORPHANS, LCK_VG_WRITE)) {
--
1.6.0.6
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