X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=ha-manager.adoc;h=3724ab3018ba40136d2b44c96580fd3b8fd1b071;hb=481a0ee4e168dcbdebe1964d32bb77cb1a283874;hp=80a11a977b050036986b29a8e4c1e978ca33c925;hpb=b207cf10705f25c4ec8eb7ad8f53391b60b6585e;p=pve-docs.git diff --git a/ha-manager.adoc b/ha-manager.adoc index 80a11a9..3724ab3 100644 --- a/ha-manager.adoc +++ b/ha-manager.adoc @@ -1017,14 +1017,14 @@ the service's group. NOTE: There are plans to add modes for (static and dynamic) load-balancing in the future. -Basic -~~~~~ +Basic Scheduler +~~~~~~~~~~~~~~~ The number of active HA services on each node is used to choose a recovery node. Non-HA-managed services are currently not counted. -Static -~~~~~~ +Static-Load Scheduler +~~~~~~~~~~~~~~~~~~~~~ IMPORTANT: The static mode is still a technology preview. @@ -1045,6 +1045,34 @@ currently not recommended to use it if you have thousands of HA managed services. +CRS Scheduling Points +~~~~~~~~~~~~~~~~~~~~~ + +The CRS algorithm is not applied for every service in every round, since this +would mean a large number of constant migrations. Depending on the workload, +this could put more strain on the cluster than could be avoided by constant +balancing. +That's why the {pve} HA manager favors keeping services on their current node. + +The CRS is currently used at the following scheduling points: + +- Service recovery (always active). When a node with active HA services fails, + all its services need to be recovered to other nodes. The CRS algorithm will + be used here to balance that recovery over the remaining nodes. + +- HA group config changes (always active). If a node is removed from a group, + or its priority is reduced, the HA stack will use the CRS algorithm to find a + new target node for the HA services in that group, matching the adapted + priority constraints. + +- HA service stopped -> start transtion (opt-in). Requesting that a stopped + service should be started is an good opportunity to check for the best suited + node as per the CRS algorithm, as moving stopped services is cheaper to do + than moving them started, especially if their disk volumes reside on shared + storage. You can enable this by setting the **`ha-rebalance-on-start`** + CRS option in the datacenter config. You can change that option also in the + Web UI, under `Datacenter` -> `Options` -> `Cluster Resource Scheduling`. + ifdef::manvolnum[] include::pve-copyright.adoc[] endif::manvolnum[]