Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=91198ac13e61c66b6... Commit: 91198ac13e61c66b65884660410311ffc8b8c24e Parent: 17ab39f7431fdad4c8a445bd1e78a288eeb64bc1 Author: David Teigland teigland@redhat.com AuthorDate: Tue Aug 26 16:40:47 2014 -0500 Committer: David Teigland teigland@redhat.com CommitterDate: Thu Oct 2 12:01:58 2014 -0500
man: lvmcache better cache mode info and other command variations
--- man/lvmcache.7.in | 49 ++++++++++++++++++++++++++++++++++++++++++------- 1 files changed, 42 insertions(+), 7 deletions(-)
diff --git a/man/lvmcache.7.in b/man/lvmcache.7.in index 6d7109a..6339b91 100644 --- a/man/lvmcache.7.in +++ b/man/lvmcache.7.in @@ -214,16 +214,27 @@ pool sub-LVs redundant. # lvconvert --type cache --cachepool vg/cache1 vg/lv1 .fi
-.SS Writethough caching +.SS Cache mode
&
-Writethrough caching ensures 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. +The default cache mode is "writethrough". Writethrough ensures 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. + +A second cache mode is "writeback". Writeback delays writing data blocks +from the cache pool back to the origin LV. This mode will increase +performance, but the loss of a device associated with the cache pool LV +can result in lost data. + +The cache mode can be specified with the --cachemode option when a cache +pool LV is created. + +.BR lvm.conf (5) +.B cache_pool_cachemode +.br +defines the default cache mode.
.nf 0. Create an origin LV we wish to cache (yours may already exist) @@ -264,6 +275,30 @@ the same VG. .br .B lvconvert --type cache-pool VG/CacheDataLV
+.SS Create a new cache LV without an existing origin LV + +& + +A cache LV can be created using an existing cache pool without an existing +origin LV. A new origin LV is created and linked to the cache pool in a +single step. + +.B lvcreate --type cache -L LargeSize -n CacheLV +.RS +.B --cachepool VG/CachePoolLV SlowPVs +.RE + + +.SS Single step cache pool LV creation + +& + +A cache pool LV can be created with a single lvcreate command, rather than +using lvconvert on existing LVs. This one command creates a cache data +LV, a cache metadata LV, and combines the two into a cache pool LV. + +.B lvcreate --type cache-pool -L CacheSize -n CachePoolLV VG FastPVs +
.SH SEE ALSO .BR lvm.conf (5),