man: lvmcache

Migrate cache description into  man(7) entry
(like lvmthin).

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.107 - 
 ==================================
+  Move cache description from lvm(8) to lvmcache(7) man page.
   Display skipped prompt in silent mode.
   Make reporting commands show help about possible sort keys on '-O help'.
   Add metadata_percent to lvs_cols.

man/Makefile.in

@@ -41,6 +41,7 @@ LVMETAD =
 endif
 
 MAN5=lvm.conf.5
+MAN7=
 MAN8=lvm-dumpconfig.8 \
 	lvchange.8 lvconvert.8 lvcreate.8 lvdisplay.8 lvextend.8 lvm.8 \
 	lvmchange.8 lvmconf.8 lvmdiskscan.8 lvmdump.8 lvmsadc.8 lvmsar.8 \
@@ -61,10 +62,12 @@ ifeq ("@BUILD_CMIRRORD@", "yes")
   MAN8CLUSTER+=cmirrord.8
 endif
 
+ifneq ("@CACHE@", "none")
+  MAN7+=lvmcache.7
+endif
+
 ifneq ("@THIN@", "none")
-  MAN7=lvmthin.7
+  MAN7+=lvmthin.7
-else
-  MAN7=
 endif
 
 MAN8DM=dmsetup.8 $(DMEVENTDMAN)
@@ -75,7 +78,7 @@ MAN8DIR=$(mandir)/man8
 MAN8SYSTEMD_GENERATORS=lvm2-activation-generator.8
 
 CLEAN_TARGETS=$(MAN5) $(MAN7) $(MAN8) $(MAN8CLUSTER) $(FSADMMAN) $(BLKDEACTIVATEMAN) $(DMEVENTDMAN) $(MAN8DM)
-DISTCLEAN_TARGETS=fsadm.8 clvmd.8 cmirrord.8 dmeventd.8 lvmthin.7 blkdeactivate.8
+DISTCLEAN_TARGETS=fsadm.8 clvmd.8 cmirrord.8 dmeventd.8 lvmcache.7 lvmthin.7 blkdeactivate.8
 
 include $(top_builddir)/make.tmpl
 

man/lvm.8.in

@@ -406,191 +406,8 @@ a command.
 Some logical volume types are simple to create and can be done with a
 single \fBlvcreate\fP(8) command.  The linear and striped logical
 volume types are an example of this.  Other logical volume types may
-require more than one command to create.  The cache and thin provisioning
+require more than one command to create.  The cache (\fBlvmcache\fP(7))
-types are examples of this.
+and thin provisioning (\fBlvmthin\fP(7)) types are examples of this.
-
-.br
-.SS Cache
-The \fIcache\fP logical volume type uses a small and fast LV to improve
-the performance of a large and slow LV.  It does this by storing the
-frequently used blocks on the faster LV.
-LVM refers to the small fast LV as a \fBcache pool LV\fP.  The large
-slow LV is called the \fBorigin LV\fP.  Due to requirements from dm-cache
-(the kernel driver), LVM further splits the cache pool LV into two
-devices - the \fBcache data LV\fP and \fBcache metadata LV\fP.  The cache
-data LV is where copies of data blocks are kept from the
-origin LV to increase speed.  The cache metadata LV holds the
-accounting information that specifies where data blocks are stored (e.g.
-on the origin LV or on the cache data LV).  Users should be familiar with
-these LVs if they wish to create the best and most robust cached
-logical volumes.
-
-.SS Cache Terms
-.nf
-origin LV           OriginLV      large slow LV
-cache data LV       CacheDataLV   small fast LV for cache pool data
-cache metadata LV   CacheMetaLV   small fast LV for cache pool metadata
-cache pool LV       CachePoolLV   CacheDataLV + CacheMetaLV
-cache LV            CacheLV       OriginLV + CachePoolLV
-.fi
-
-.SS Cache Steps
-The steps to create a logical volume of \fIcache\fP type are as follows:
-.TP
-0.
-Create an LV or identify an existing LV to be the origin LV.
-.TP
-1.
-Create the cache data LV.  The size of this LV is the size of the cache
-and will be reported as the size of the cache pool LV.
-.TP
-2.
-Create the cache metadata LV.
-The size of this LV should be 1000 times smaller than the cache data LV
-with a minimum size of 8MiB.
-.TP
-3.
-Create the cache pool LV by combining the cache data LV (from step 1)
-and cache metadata LV (from step 2).  When performing this step,
-behavioral characteristics of the cache pool LV can be set.
-The name of the cache pool LV takes the name of the cache data LV and
-the cache data LV and cache metadata LV are renamed
-to CachePoolLV_cdata and CachePoolLV_cmeta.
-.TP
-4.
-Create a cache LV by linking the cache pool LV to the origin LV.
-The user accessible cache LV takes the name of the origin LV,
-while the origin LV becomes a hidden LV with the name
-OriginLV_corig.  Users can perform this step while the origin LV
-is in use.
-
-.P
-The steps above represent the best way to create a cache LV.
-They provide the most options and have the ability to create the
-most robust logical volumes.  The examples below illustrate how these
-steps might be used in practice.
-
-.SS Cache Commands
-.nf
-0. create OriginLV
-lvcreate -L LargeSize -n OriginLV VG SlowPVs
-
-1. create CacheDataLV
-lvcreate -L CacheSize -n CacheDataLV VG FastPVs
-
-2. create CacheMetaLV
-lvcreate -L MetaSize -n CacheMetaLV VG FastPVs
-
-3. create CachePoolLV
-lvconvert --type cache-pool --poolmetadata VG/CacheMetaLV VG/CacheDataLV
-CachePoolLV takes the name of CacheDataLV.
-CacheDataLV is renamed CachePoolLV_cdata and becomes hidden.
-CacheMetaLV is renamed CachePoolLV_cmeta and becomes hidden.
-
-4. create CacheLV
-lvconvert --type cache --cachepool VG/CachePoolLV VG/OriginLV
-CacheLV takes the name of OriginLV.
-OriginLV is renamed OriginLV_corig and becomes hidden.
-.fi
-
-.SS Cache Examples
-
-.B Example 1:
-Creating a simple cache LV.
-.br
-
-.nf
-0. Create the origin LV
-# lvcreate -L 10G -n lvx vg /dev/slow_dev
-
-1. Create a cache data LV
-# lvcreate -L 1G -n lvx_cache vg /dev/fast_dev
-
-2. Create a cache metadata LV (~1/1000th size of CacheDataLV or 8MiB)
-# lvcreate -L 8M -n lvx_cache_meta vg /dev/fast_dev
-
-3. Create a cache pool LV, combining cache data LV and cache metadata LV
-# lvconvert --type cache-pool --poolmetadata vg/lvx_cache_meta \\
-	vg/lvx_cache
-
-4. Create a cached LV by combining the cache pool LV and origin LV
-# lvconvert --type cache --cachepool vg/lvx_cache vg/lvx
-.fi
-
-.B Example 2:
-Creating a cache LV with a fault tolerant cache pool LV.
-
-Users who are concerned about the possibility of failures in their fast devices
-that could lead to data loss might consider making their cache pool sub-LVs
-redundant.  Example 2 illustrates how to do that.  Note that only steps
-1 & 2 change.
-
-.nf
-0. Create an origin LV we wish to cache
-# lvcreate -L 10G -n lvx vg /dev/slow_devs
-
-1. Create a 2-way RAID1 cache data LV
-# lvcreate --type raid1 -m 1 -L 1G -n lvx_cache vg \\
-	/dev/fast1 /dev/fast2
-
-2. Create a 2-way RAID1 cache metadata LV
-# lvcreate --type raid1 -m 1 -L 8M -n lvx_cache_meta vg \\
-	/dev/fast1 /dev/fast2
-
-3. Create a cache pool LV combining cache data LV and cache metadata LV
-# lvconvert --type cache-pool --poolmetadata vg/lvx_cache_meta \\
-	vg/lvx_cache
-
-4. Create a cached LV by combining the cache pool LV and origin LV
-# lvconvert --type cache --cachepool vg/lvx_cache vg/lvx
-.fi
-
-.B Example 3:
-Creating a simple cache LV with \fIwritethough\fP caching.
-
-Some users wish to ensure that any data written will be stored both in the
-cache pool LV and on the origin LV.  The loss of a device associated with
-the cache pool LV in this case would not mean the loss of any data.  When
-combining the cache data LV and the cache metadata LV to form the cache pool
-LV, properties of the cache can be specified - in this case,
-\fIwritethrough\fP vs. \fIwriteback\fP.  Note that only step 3 is affected
-in this case.
-
-.nf
-0. Create an origin LV we wish to cache (yours may already exist)
-# lvcreate -L 10G -n lvx vg /dev/slow
-
-1. Create a cache data LV
-# lvcreate -L 1G -n lvx_cache vg /dev/fast
-
-2. Create a cache metadata LV
-# lvcreate -L 8M -n lvx_cache_meta vg /dev/fast
-
-3. Create a cache pool LV specifying cache mode "writethrough"
-# lvconvert --type cache-pool --poolmetadata vg/lvx_cache_meta \\
-	--cachemode writethrough vg/lvx_cache
-
-4. Create a cache LV by combining the cache pool LV and origin LV
-# lvconvert --type cache --cachepool vg/lvx_cache vg/lvx
-.fi
-
-.SS Removing Cache Logical Volumes
-If you wish to remove all logical volumes associated with a cache
-LV, you must remove both top-level, user-visible devices.
-The cache metadata LV and cache data LV cannot be removed
-directly.  If only the cache pool LV is specfied for removal, any cached
-blocks not yet on the origin LV will be flush, the cache pool LV will be
-removed, and the now un-cached origin LV will remain.  If the user
-specifies a cache LV for removal, then the origin LV is
-removed and only the cache pool LV will remain.  The cache pool LV can then
-be used to create another cache LV with a different origin LV if desired.
-
-When users intend to remove all logical volumes associated with a
-cache LV, it is generally better to start with the origin LV and then
-remove the cache pool LV.  If the operations are performed in the
-reverse order, the user will have to wait for the contents of the
-cache pool LV to be flushed before the origin LV is removed.  This
-could take some time.
 
 .SH DIAGNOSTICS
 All tools return a status code of zero on success or non-zero on failure.
@@ -600,6 +417,8 @@ All tools return a status code of zero on success or non-zero on failure.
 .I $HOME/.lvm_history
 .SH SEE ALSO
 .BR lvm.conf (5),
+.BR lvmcache (7),
+.BR lvmthin (7),
 .BR lvm\ dumpconfig (8),
 .BR clvmd (8),
 .BR lvchange (8),

spec/packages.inc

@@ -83,6 +83,7 @@ fi
  %{_sbindir}/lvmetad
 %endif
 %{_mandir}/man5/lvm.conf.5.gz
+%{_mandir}/man7/lvmcache.7.gz
 %{_mandir}/man7/lvmthin.7.gz
 %{_mandir}/man8/fsadm.8.gz
 %{_mandir}/man8/lvchange.8.gz