SPAM: [PATCH docs] pveum: Add information about realm certificates

[pve-docs.git] / vzdump.adoc

diff --git a/vzdump.adoc b/vzdump.adoc
index e990982c9c6df501df3ed29f6b8c788f2044baca..1c396804f0cf9b08c8d8bc44231d4a760778acc6 100644 (file)
--- a/vzdump.adoc
+++ b/vzdump.adoc
@@ -78,17 +78,17 @@ consistency, the use of the `snapshot` mode is recommended instead.
 `snapshot` mode::
 
 This mode provides the lowest operation downtime, at the cost of a
-small inconsistency risk.  It works by performing a Proxmox VE live
+small inconsistency risk. It works by performing a {pve} live
 backup, in which data blocks are copied while the VM is running. If the
 guest agent is enabled (`agent: 1`) and running, it calls
 `guest-fsfreeze-freeze` and `guest-fsfreeze-thaw` to improve
 consistency.
 
-A technical overview of the Proxmox VE live backup for QemuServer can
+A technical overview of the {pve} live backup for QemuServer can
 be found online
 https://git.proxmox.com/?p=pve-qemu.git;a=blob_plain;f=backup.txt[here].
 
-NOTE: Proxmox VE live backup provides snapshot-like semantics on any
+NOTE: {pve} live backup provides snapshot-like semantics on any
 storage type. It does not require that the underlying storage supports
 snapshots. Also please note that since the backups are done via 
 a background Qemu process, a stopped VM will appear as running for a 
@@ -147,6 +147,39 @@ That way it is possible to store several backup in the same
 directory. The parameter `maxfiles` can be used to specify the
 maximum number of backups to keep.
 
+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.
+
+
 [[vzdump_restore]]
 Restore
 -------
@@ -200,10 +233,10 @@ time, thus we implemented the possibility to set a default bandwidth limit
 per configured storage, this can be done with:
 
 ----
-# pvesm set STORAGEID --bwlimit KIBs
+# pvesm set STORAGEID --bwlimit restore=KIBs
 ----
 
-
+[[vzdump_configuration]]
 Configuration
 -------------