[pve-devel] [PATCH docs 4/7] pvecm: extend cluster Requirements
Aaron Lauterer
a.lauterer at proxmox.com
Tue Apr 29 15:57:46 CEST 2025
by expanding on best practices with background information as to how and
why.
Signed-off-by: Aaron Lauterer <a.lauterer at proxmox.com>
---
pvecm.adoc | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/pvecm.adoc b/pvecm.adoc
index 3b9cfc4..c50ec15 100644
--- a/pvecm.adoc
+++ b/pvecm.adoc
@@ -68,9 +68,24 @@ Requirements
* If you are interested in High Availability, you need to have at
least three nodes for reliable quorum. All nodes should have the
same version.
++
+NOTE: For smaller 2-node clusters, the xref:_corosync_external_vote_support[QDevice]
+can be used to provide a 3rd vote.
-* We recommend a dedicated NIC for the cluster traffic, especially if
- you use shared storage.
+* We recommend a dedicated physical NIC for the cluster traffic.
++
+NOTE: The {pve} cluster communication uses the Corosync protocol. It needs consistent
+low latency but not a lot of bandwidth. A dedicated 1 Gbit NIC is enough in
+most situations. It helps to avoid situations where other services can use up
+all the available bandwidth. Which in turn would increase the latency for the
+Corosync packets.
+
+* Configuring additional links for the cluster traffic can help in situations where
+ the dedicated network is down.
++
+NOTE: The Corosync protocol used for the {pve} cluster communication can
+switch between multiple networks by itself and does not rely on a bonded network
+for redundancy. You can configure up to 8 networks to be used by Corosync.
* The root password of a cluster node is required for adding nodes.
--
2.39.5
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