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| Both sides previous revision Previous revision Next revision | Previous revision | ||
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vm:proxmox:ceph:performance [2024/05/17 19:10] niziak |
vm:proxmox:ceph:performance [2024/05/19 10:39] (current) niziak |
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| * same number of primary PG per OSD = read operations spread evenly | * same number of primary PG per OSD = read operations spread evenly | ||
| * primary PG - original/first PG - others are replicas. Primary PG is used for read. | * primary PG - original/first PG - others are replicas. Primary PG is used for read. | ||
| + | * use relatively more PG than for big cluster - better balance, but handling PGs consumes resources (RAM) | ||
| + | * i.e. for 7 OSD x 2TB PG autoscaler recommends 256 PG. After changing to 384 IOops drastivally increases and latency drops. | ||
| + | Setting to 512 PG wasn't possible because limit of 250PG/OSD. | ||
| === balancer === | === balancer === | ||
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| It is possible to set desired/target size of pool. This prevents autoscaler to move data every time new data are stored. | It is possible to set desired/target size of pool. This prevents autoscaler to move data every time new data are stored. | ||
| + | |||
| + | ==== check cluster balance ==== | ||
| + | |||
| + | ceph -s | ||
| + | ceph osd df - shows standard deviation | ||
| + | |||
| + | no tools to show primary PG balancing. Tool on https://github.com/JoshSalomon/Cephalocon-2019/blob/master/pool_pgs_osd.sh | ||
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| ==== performance on slow HDDs ==== | ==== performance on slow HDDs ==== | ||