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--- software:files [2024/04/13 15:03]
cyril [Tools] borg usage
+++ software:files [2024/04/14 17:54]
cyril [Tools]
@@ Line 158: / Line 158: @@
   * Create archives: <code>borg create <repo>::<!archive> <path> --stats --progress
     --compression auto,zstd,12 --chunker-params 15,23,19,4095 --noatime --noctime -x --exclude-caches</code>
-    * ''--compression'': it can make sense to adjust the compression level depending on your computer speed and your storage speed, so that compression does not slow down the backup, but still save as much space as possible under this constraint. You have roughly the choice between LZ4 (very quick), LZMA (very high compression ratio), and ZSTD (wide-range) in between.
+    * ''--compression'': it can make sense to adjust the compression level depending on your computer speed and your storage speed, so that compression does not slow down the backup, but still save as much space as possible under this constraint. However it is not always easy to find an universal value (data that compress very well are mostly limited by the input storage speed, while data that compress less well are mostly limited by the output storage speed). You have roughly the choice between LZ4 (very quick), LZMA (very high compression ratio), and ZSTD (wide-range) in between.
     * ''--chunker-params'': this is also an important but a bit complicated tuning. Originally default value was creating small chunks causing huge cache and memory usage, so they switched to much larger chunks, but which can be too large for some applications (for instance when modifying only metadata of an image file, we want to deduplicate the data), so I came with this compromise ''15,23,19,4095''.
   * ''borg info <repo>''