From 65b0b42f47ff0bf9451bee167676ac44ed9abd93 Mon Sep 17 00:00:00 2001 From: Alasdair Kergon Date: Wed, 17 Nov 2004 17:49:32 +0000 Subject: [PATCH] More lvm.conf and tagging documentation. --- man/lvm.conf.5 | 166 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 162 insertions(+), 4 deletions(-) diff --git a/man/lvm.conf.5 b/man/lvm.conf.5 index 57d03bbf6..104ed5a50 100644 --- a/man/lvm.conf.5 +++ b/man/lvm.conf.5 @@ -112,7 +112,8 @@ Example: \fBtypes = ["fd", 16]\fP. To create physical volumes on device-mapper volumes created outside LVM2, perhaps encrypted ones from \fBcryptsetup\fP, you'll need \fBtypes = ["device-mapper", 16]\fP. But if you do this, -be careful to avoid recursion within LVM2. +be careful to avoid recursion within LVM2. The figure for number +of partitions is not currently used in LVM2 - and might never be. .IP \fBsysfs_scan\fP (em If set to 1 and your kernel supports sysfs and it is mounted, sysfs will be used as a quick way of filtering out @@ -210,10 +211,167 @@ Defaults to /proc. Interpreted as octal if the first digit is zero. Defaults to 077. Use 022 to allow other users to read the files by default. +.IP +\fBformat\fP \(em The default value of \fB--metadatatype\fP used +to determine which format of metadata to use when creating new +physical volumes and volume groups. \fBlvm1\fP or \fBlvm2\fP. +.IP +\fBfallback_to_lvm1\fP \(em Set this to 1 if you need to +be able to switch between 2.4 kernels using LVM1 and kernels +including device-mapper. +The LVM2 tools should be installed as normal and +the LVM1 tools should be installed with a .lvm1 suffix e.g. +vgscan.lvm1. +If an LVM2 tool is then run but unable to communicate +with device-mapper, it will automatically invoke the equivalent LVM1 +version of the tool. Note that for LVM1 tools to +manipulate physical volumes and volume groups created by LVM2 you +must use \fB--metadataformat lvm1\fP when creating them. +.IP +\fBlibrary_dir\fP \(em A directory searched for LVM2's shared libraries +ahead of the places \fBdlopen\fP (3) searches. +.IP +\fBformat_libraries\fP \(em A list of shared libraries to load that contain +code to process different formats of metadata. For example, liblvm2formatpool.so +is needed to read GFS pool metadata if LVM2 was configured \fB--with-pool=shared\fP. +.IP +\fBlocking_type\fP \(em What type of locking to use. +1 is the default, which use flocks on files in \fBlocking_dir\fP +(see below) to +avoid conflicting LVM2 commands running concurrently on a single +machine. 0 disables locking and risks corrupting your metadata. +If set to 2, the tools will load the external \fBlocking_library\fP +(see below). +If the tools were configured \fB--with-cluster=internal\fP +(the default) then 3 means to use built-in cluster-wide locking. +All changes to logical volumes and their states are communicated +using locks. +.IP +\fBlocking_dir\fP \(em The directory LVM2 places its file locks +if \fBlocking_type\fP is set to 1. The default is \fB/var/lock/lvm\fP. +.IP +\fBlocking_library\fP \(em The name of the external locking +library to load if \fBlocking_type\fP is set to 2. +The default is \fBlvm2_locking.so\fP. If you need to write +such a library, look at the lib/locking source code directory. +.TP +\fBtags\fP \(em Host tag settings +.IP +\fBhosttags\fP \(em If set to 1, create a host tag with the machine name. +Setting this to 0 does nothing, neither creating nor destroying any tag. +The machine name used is the nodename as returned by \fBuname\fP (2). +.IP +Additional host tags to be set can be listed here as subsections. +The @ prefix for tags is optional. +Each of these host tag subsections can contain a \fBhost_list\fP +array of host names. If any one of these entries matches the machine +name exactly then the host tag gets defined on this particular host, +otherwise it doesn't. +.IP +After lvm.conf has been processed, LVM2 works through each host +tag that has been defined in turn, and if there is a configuration +file called lvm_\fB\fP.conf it attempts to load it. +Any settings read in override settings found in earlier files. +Any additional host tags defined get appended to the search list, +so in turn they can lead to further configuration files being processed. +Use \fBlvm dumpconfig\fP to check the result of config +file processing. +.IP +The following example always sets host tags \fBtag1\fP and +sets \fBtag2\fP on machines fs1 and fs2: +.IP +tags { tag1 { } tag2 { host_list = [ "fs1", "fs2" ] } } +.IP +These options are useful if you are replicating configuration files +around a cluster. Use of \fBhosttags = 1\fP means every machine +can have static and identical local configuration files yet use +different settings and activate different logical volumes by +default. See also \fBvolume_list\fP below and \fB--addtag\fP +in \fBlvm\fP (8). +.TP +\fBactivation\fP \(em Settings affecting device-mapper activation +.IP +\fBmissing_stripe_filler\fP \(em When activating an incomplete +logical volume in partial mode, this missing data is replaced +with this device. It could perhaps be a block device that always +returns an error when it is accessed, or one that always +returns zeros. See \fBlvcreate\fP (8) for how to create +such devices. +.IP +\fBmirror_region_size\fP \(em Unit size in KB for copy operations +when mirroring. +.IP +\fBreserved_memory\fP, \fBreserved_stack\fP \(em How many KB to reserve +for LVM2 to use while logical volumes are suspended. If insufficient +memory is reserved before suspension, there is a risk of machine deadlock. +.IP +\fBprocess_priority\fP \(em The nice value to use while devices are +suspended. This is set to a high priority so that logical volumes +are suspended (with I/O generated by other processes to those +logical volumes getting queued) for the shortest possible time. +.IP +\fBvolume_list\fP \(em This acts as a filter through which +all requests to activate a logical volume on this machine +are passed. A logical volume is only activated if it matches +an item in the list. Tags must be preceded by @ and are checked +against all tags defined in the logical volume and volume group +metadata for a match. +@* is short-hand to check every tag set on the host machine (see +\fBtags\fP above). +Logical volume and volume groups can also be included in the list +by name e.g. vg00, vg00/lvol1. +.TP +\fBmetadata\fP \(em Advanced metadata settings +.IP +\fBpvmetadatacopies\fP \(em When creating a physical volume using the +LVM2 metadata format, this is the default number of copies of metadata +to store on each physical volume. +Currently it can be set to 0, 1 or 2. The default is 1. +If set to 2, one copy is placed at the beginning of the disk +and the other is placed at the end. +It can be overridden on the command line with \fB--metadatacopies\fP. +If creating a volume group with just one physical volume, it's a +good idea to have 2 copies. If creating a large volume group with +many physical volumes, you may decide that 3 copies of the metadata +is sufficient, i.e. setting it to 1 on three of the physical volumes, +and 0 on the rest. Every volume group must contain at least one +physical volume with at least 1 copy of the metadata (unless using +the text files described below). The disadvantage of having lots +of copies is that every time the tools access the volume group, every +copy of the metadata has to be accessed, and this slows down the +tools. +.IP +\fBpvmetadatasize\fP \(em Approximate number of sectors to set aside +for each copy of the metadata. Volume groups with large numbers of +physical or logical volumes, or volumes groups containing complex +logical volume structures will need additional space for their metadata. +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 +\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 +here, preferably on different (non-logical-volume) filesystems +and with no other on-disk metadata, \fBpvmetadatacopies = 0\fP. +Alternatively these directories can be in addition to the +on-disk metadata areas. This feature was created during the +development of the LVM2 metadata before the new on-disk metadata +areas were designed and no longer gets tested. +It is not supported under low-memory conditions, and it is +important never to edit these metadata files unless you fully +understand how things work: to make changes you should always use +the tools as normal, or else vgcfgbackup, edit backup, vgcfgrestore. .SH FILES .I /etc/lvm/lvm.conf +.I /etc/lvm/.cache +.I /etc/lvm/archive +.I /etc/lvm/backup +.I /var/lock/lvm .SH SEE ALSO -.BR lvm (8) -.BR umask (2) -.BR syslog (3) +.BR lvm (8), +.BR umask (2), +.BR uname (2), +.BR dlopen (3), +.BR syslog (3), .BR syslog.conf (5)