+That way it is possible to store several backup in the same directory. You can
+limit the number of backups that are kept with various retention options, see
+the xref:vzdump_retention[Backup Retention] section below.
+
+Backup File Compression
+-----------------------
+
+The backup file can be compressed with one of the following algorithms: `lzo`
+footnote:[Lempel–Ziv–Oberhumer a lossless data compression algorithm
+https://en.wikipedia.org/wiki/Lempel-Ziv-Oberhumer], `gzip` footnote:[gzip -
+based on the DEFLATE algorithm https://en.wikipedia.org/wiki/Gzip] or `zstd`
+footnote:[Zstandard a lossless data compression algorithm
+https://en.wikipedia.org/wiki/Zstandard].
+
+Currently, Zstandard (zstd) is the fastest of these three algorithms.
+Multi-threading is another advantage of zstd over lzo and gzip. Lzo and gzip
+are more widely used and often installed by default.
+
+You can install pigz footnote:[pigz - parallel implementation of gzip
+https://zlib.net/pigz/] as a drop-in replacement for gzip to provide better
+performance due to multi-threading. For pigz & zstd, the amount of
+threads/cores can be adjusted. See the
+xref:vzdump_configuration[configuration options] below.
+
+The extension of the backup file name can usually be used to determine which
+compression algorithm has been used to create the backup.
+
+|===
+|.zst | Zstandard (zstd) compression
+|.gz or .tgz | gzip compression
+|.lzo | lzo compression
+|===
+
+If the backup file name doesn't end with one of the above file extensions, then
+it was not compressed by vzdump.
+
+Backup Encryption
+-----------------
+
+For Proxmox Backup Server storages, you can optionally set up client-side
+encryption of backups, see xref:storage_pbs_encryption[the corresponding section.]
+
+[[vzdump_retention]]
+Backup Retention
+----------------
+
+With the `prune-backups` option you can specify which backups you want to keep
+in a flexible manner. The following retention options are available:
+
+`keep-all <boolean>` ::
+Keep all backups. If this is `true`, no other options can be set.
+
+`keep-last <N>` ::
+Keep the last `<N>` backups.
+
+`keep-hourly <N>` ::
+Keep backups for the last `<N>` hours. If there is more than one
+backup for a single hour, only the latest is kept.
+
+`keep-daily <N>` ::
+Keep backups for the last `<N>` days. If there is more than one
+backup for a single day, only the latest is kept.
+
+`keep-weekly <N>` ::
+Keep backups for the last `<N>` weeks. If there is more than one
+backup for a single week, only the latest is kept.
+
+NOTE: Weeks start on Monday and end on Sunday. The software uses the
+`ISO week date`-system and handles weeks at the end of the year correctly.
+
+`keep-monthly <N>` ::
+Keep backups for the last `<N>` months. If there is more than one
+backup for a single month, only the latest is kept.
+
+`keep-yearly <N>` ::
+Keep backups for the last `<N>` years. If there is more than one
+backup for a single year, only the latest is kept.
+
+The retention options are processed in the order given above. Each option
+only covers backups within its time period. The next option does not take care
+of already covered backups. It will only consider older backups.
+
+Specify the retention options you want to use as a
+comma-separated list, for example:
+
+ # vzdump 777 --prune-backups keep-last=3,keep-daily=13,keep-yearly=9
+
+While you can pass `prune-backups` directly to `vzdump`, it is often more
+sensible to configure the setting on the storage level, which can be done via
+the web interface.
+
+NOTE: The old `maxfiles` option is deprecated and should be replaced either by
+`keep-last` or, in case `maxfiles` was `0` for unlimited retention, by
+`keep-all`.
+