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man lvmcache: include chunk size

This commit is contained in:
David Teigland 2015-11-23 11:57:41 -06:00
parent c026846739
commit fe64d3a2e2

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@ -301,6 +301,35 @@ defines the default cache policy.
defines the default cache settings.
.SS Chunk size
\&
The size of data blocks managed by a cache pool can be specified with the
\-\-chunksize option when the cache LV is created. The default unit
is KiB. The value must be a multiple of 32KiB between 32KiB and 1GiB.
Using a chunk size that is too large can result in wasteful use of the
cache, where small reads and writes can cause large sections of an LV to
be mapped into the cache. However, choosing a chunk size that is too
small can result in more overhead trying to manage the numerous chunks
that become mapped into the cache. Overhead can include both excessive
CPU time searching for chunks, and excessive memory tracking chunks.
Command to display the cache pool LV chunk size:
.br
.B lvs \-o+chunksize VG/CacheLV
.BR lvm.conf (5)
.B cache_pool_chunk_size
.br
controls the default chunk size used when creating a cache LV.
The default value is shown by:
.br
.B lvmconfig \-\-type default allocation/cache_pool_chunk_size
.SS Spare metadata LV
\&