Differences

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--- vm:proxmox:ceph:pg [2023/07/03 20:28] – created niziak
+++ vm:proxmox:ceph:pg [2023/07/11 12:06] (current) – niziak
@@ Line 2: / Line 2: @@
 PG
+===== Calculations =====
+  * [[https://old.ceph.com/pgcalc/]]
+  * Max PG per OSD is 300
+  * Result must be rounded up to the nearest power of 2.
+===== reweight =====
+Adjust reweight according to current OSD utilisation - to prevent filling one OSD
+<code bash>ceph osd reweight-by-utilization</code>
+In CRUSH hierarchies with a smaller number of OSDs, it’s possible for some OSDs
+to get more PGs than other OSDs, resulting in a higher load. You can reweight
+OSDs by PG distribution to address this situation by executing the following:
+<code bash>ceph osd reweight-by-pg 101</code>
+NOTE: 101 is a ''oload'' parameter, which means ''overload percentage for consideration 101%''. For example, an argument of 200 would reweight OSDs which are twice as utilized as the average OSD.
+===== Balancer =====
+When the cluster is healthy, the balancer will incrementally move a small fraction of unbalanced PGs in order to improve distribution. This fraction will not exceed a certain threshold that defaults to 5%.
+Set it to 1%:
+<code bash>ceph config set mgr target_max_misplaced_ratio .01</code>