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--- general:linux:lvmcache [2020/11/17 22:19] – created sunkan
+++ general:linux:lvmcache [2021/02/11 08:25] (current) – [And now reattach the cache] sunkan
@@ Line 184: / Line 184: @@
   WARNING: Cached thin pool's data cannot be currently resized and require manual uncache before resize!
   Logical volume F3_2TB/ThinPool0_tdata is now cached.
+</code>
+===== Extending size of ThinPool0 =====
+==== Remove caching from the thinpool ====
+As it does not seem to be possible to extend a cached thinpool, we first need to remove the cache.
+Follow first two steps above from section "Removing cache from ThinPool0" (do not re-attach the cache of course)
+Some - before information
+<code>
+bigbang:~# lvdisplay -a F3_2TB/ThinPool0_tdata
+  --- Logical volume ---
+  Internal LV Name       ThinPool0_tdata
+  VG Name                F3_2TB
+  LV UUID                Fyc9Md-c1XD-xpib-dJDw-Obr4-SYL5-G88yqS
+  LV Write Access        read/write
+  LV Creation host, time bigbang, 2019-10-12 14:17:30 +0200
+  LV Cache pool name     ThinPool0_CDLV
+  LV Cache origin name   ThinPool0_tdata_corig
+  LV Status              available
+  # open                 1
+  LV Size                500.00 GiB
+  Cache used blocks      99.99%
+  Cache metadata blocks  18.54%
+  Cache dirty blocks     0.00%
+  Cache read hits/misses 644218163 / 453243621
+  Cache wrt hits/misses  1046297083 / 31441523
+  Cache demotions        1455727
+  Cache promotions       1455727
+  Current LE             128000
+  Segments               1
+  Allocation             inherit
+  Read ahead sectors     auto
+  - currently set to     256
+  Block device           253:36
+</code>
+<code>
+bigbang:~# lvchange --cachemode writethrough F3_2TB/ThinPool0_tdata
+  Flushing 55 blocks for cache F3_2TB/ThinPool0_tdata.
+  Logical volume F3_2TB/ThinPool0_tdata changed.
+</code>
+<code>
+bigbang:~# lvconvert --splitcache F3_2TB/ThinPool0
+  Logical volume F3_2TB/ThinPool0_tdata is not cached and cache pool F3_2TB/ThinPool0_CDLV is unused.
+</code>
+==== Now extend the ThinPool0 LV ====
+<code>
+bigbang:~# lvextend -L 1t F3_2TB/ThinPool0
+  Size of logical volume F3_2TB/ThinPool0_tdata changed from 500.00 GiB (128000 extents) to 1.00 TiB (262144 extents).
+  Logical volume F3_2TB/ThinPool0_tdata successfully resized.
+</code>
+==== And now reattach the cache ====
+Do the last step from section "Removing cache from ThinPool0" to reattach the cache to the thinpool
+<code>
+bigbang:~# lvconvert --type cache --cachemode writeback --cachepool F3_2TB/ThinPool0_CDLV F3_2TB/ThinPool0
+Do you want wipe existing metadata of cache pool F3_2TB/ThinPool0_CDLV? [y/n]: y
+  WARNING: Cached thin pool's data cannot be currently resized and require manual uncache before resize!
+  Logical volume F3_2TB/ThinPool0_tdata is now cached.
+</code>
+And some "after" information
+<code>
+bigbang:~# lvdisplay -a F3_2TB/ThinPool0_tdata
+  --- Logical volume ---
+  Internal LV Name       ThinPool0_tdata
+  VG Name                F3_2TB
+  LV UUID                Fyc9Md-c1XD-xpib-dJDw-Obr4-SYL5-G88yqS
+  LV Write Access        read/write
+  LV Creation host, time bigbang, 2019-10-12 14:17:30 +0200
+  LV Cache pool name     ThinPool0_CDLV
+  LV Cache origin name   ThinPool0_tdata_corig
+  LV Status              available
+  # open                 1
+  LV Size                1.00 TiB
+  Cache used blocks      0.13%
+  Cache metadata blocks  12.46%
+  Cache dirty blocks     10.12%
+  Cache read hits/misses 0 / 36
+  Cache wrt hits/misses  3663 / 1530
+  Cache demotions        0
+  Cache promotions       1067
+  Current LE             262144
+  Segments               1
+  Allocation             inherit
+  Read ahead sectors     auto
+  - currently set to     256
+  Block device           253:36
 </code>