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--- software:files [2024/04/14 17:54]
cyril [Tools]
+++ software:files [2024/04/19 14:27]
cyril [Maintenance]
@@ Line 128: / Line 128: @@
   * With ''btrfs'':
-    * ''compsize <subvolume-path>'' in order to get statistics about quantity of compressed files, and compression ratio
+    * ''compsize <subvolume-path>'' in order to get statistics about quantity of compressed files, and compression ratio.
+    * ''compsize <file-path>'' in order to get compression details about a specific file.
+=== SSD TRIM ===
+  * TRIM (or discard) operation means informing the SSD drive about the unused memory, so that it can perform efficiently wear leveling.
+  * Checking TRIM support: run ''lsblk --discard'', and check for non-zero values in columns DISC-GRAN (DISCard GRANularity) and DISC-MAX
+  * Each layer must forward the TRIM commands to the layer above, until it reaches the drive:
+    * dm-crypt. Depending on how the encrypted volume is mounted, different possibilities:
+      * ''cryptsetup <...> --allow-discards''
+      * set option ''discard'' in ''/etc/crypttab''
+      * set option ''cryptdevice=<device>:root:allow-discards'' in kernel parameters for root partition
+    * LVM
+  * Two options are available:
+    * Continuous TRIM, i.e. configuring the filesystem to notify instantly each block that is freed.
+      * It is not advised because can cause issues.
+    * Periodic TRIM, i.e. explicitly notifying the free blocks periodically.
+      * Using the ''fstrim'' utils from the util-linux package.
+Source : https://wiki.archlinux.org/title/Solid_state_drive
 === Resizing ===
@@ Line 177: / Line 197: @@
+===== Container files =====
+Sources:
+  * [[https://serverfault.com/questions/696554/creating-a-grow-on-demand-encrypted-volume-with-luks|Excellent demonstration]] for creating a growing container file with LUKS and EXT4 using sparse files.
 ===== Digital Will =====