Ceph - 1 subtrees have committed pool target_size_bytes

[Sidhana]

Hello everyone
We have gotten this failure on our 3 nodes cluster and I really don't know how to solve it.
I would really appreciate the help.
Thanks in advance

 

[Alwin Antreich]

Check your total of the target_size_bytes, it could be bigger than the "Raw Capacity" available. If not then the BIAS can play a role as well, which acts as a multiplier for increasing the number of PGs. In short, the autoscaler assumes in the future you may be using more space then the raw capacity.

Have a look at the docs for the autscaler: https://docs.ceph.com/en/latest/rad...nt-groups/#viewing-pg-scaling-recommendations

I recommend to use the "Target Ratio" instead of the "Target Size" which will use a floating ratio relative to the pools on the same crush device class.

 

[Sidhana]

Check your total of the target_size_bytes, it could be bigger than the "Raw Capacity" available. If not then the BIAS can play a role as well, which acts as a multiplier for increasing the number of PGs. In short, the autoscaler assumes in the future you may be using more space then the raw capacity.

Have a look at the docs for the autscaler: https://docs.ceph.com/en/latest/rad...nt-groups/#viewing-pg-scaling-recommendations

I recommend to use the "Target Ratio" instead of the "Target Size" which will use a floating ratio relative to the pools on the same crush device class.

Thanks for the quick reply
The target_size_bytes isn't bigger than the "Raw Capacity"

We have 3 Nodes
15 OSDs in total (5 each) (more will be added in the future)
25 Storage Pools (more will be added)

what percentage of Target Ratio would you suggest?

 

[Alwin Antreich]

The RATIO is calculated by (SIZE * RATE) / RAW CAPACITY, the EFFECTIVE RATIO is then the one which will be applied towards the cluster size. You can turn autoscaling to warn or disable autoscaling for the pool, and then fiddle with the ratios till you are satisfied.

ceph osd pool set <pool-name> pg_autoscale_mode <mode>
# or
ceph osd pool set <pool-name> noautoscale

The autoscaler is providing an automated way to increase or decrease the PGs for a pool.