Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=3bd9d81b29fb8ba490d87b... Commit: 3bd9d81b29fb8ba490d87b3557861bf00047855d Parent: ae5634a8be3eedb556325a4b81540896fa6cac16 Author: David Teigland teigland@redhat.com AuthorDate: Thu Jun 11 17:01:01 2020 -0500 Committer: David Teigland teigland@redhat.com CommitterDate: Mon Jun 22 11:24:02 2020 -0500

man: lvmcache info about cachedevice usage

--- man/lvmcache.7_main | 30 ++++++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/man/lvmcache.7_main b/man/lvmcache.7_main index 425904e4a..244ea1e48 100644 --- a/man/lvmcache.7_main +++ b/man/lvmcache.7_main @@ -34,8 +34,6 @@ LVM refers to this using the LV type \fBwritecache\fP.

.SH USAGE

-Both kinds of caching use similar lvm commands: - .B 1. Identify main LV that needs caching

The main LV may already exist, and is located on larger, slower devices. @@ -133,6 +131,22 @@ attached. main vg -wi------- linear /dev/slow_hhd .fi

+.SS Create a new LV with caching. + +A new LV can be created with caching attached at the time of creation +using the following command: + +.nf +$ lvcreate --type cache|writecache -n Name -L Size + --cachedevice /dev/fast_ssd vg /dev/slow_hhd +.fi + +The main LV is created with the specified Name and Size from the slow_hhd. +A hidden fast LV is created on the fast_ssd and is then attached to the +new main LV. If the fast_ssd is unused, the entire disk will be used as +the cache unless the --cachesize option is used to specify a size for the +fast LV. The --cachedevice option can be repeated to use multiple disks +for the fast LV.

.SH OPTIONS

@@ -162,6 +176,18 @@ that cannot be used directly. If a standard LV is passed with this option, lvm will first convert it to a cache pool by combining it with another LV to use for metadata. This option can be used with dm-cache.

+.B --cachedevice +.I PV +.br + +This option can be used in place of --cachevol, in which case a cachevol +LV will be created using the specified device. This option can be +repeated to create a cachevol using multiple devices, or a tag name can be +specified in which case the cachevol will be created using any of the +devices with the given tag. If a named cache device is unused, the entire +device will be used to create the cachevol. To create a cachevol of a +specific size from the cache devices, include the --cachesize option. + &

.SS dm-cache block size