datastore space anomaly

Oct 9, 2024
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I migrated the VMs that resided in a ZFS pool to a CEPH pool, but I noticed that on the Ceph datastore the space they occupy is much less, why is there this difference?
 
Maybe you didn't use Thin Provision previously or had old snapshots lying around? How/where did you check?
 
I migrated 4 vm of 1TB each on the ceph datastore, but if I view the occupied space it does not exceed 1 2 TB, but in reality it should occupy 4 TB, why is there this difference?
 
Hi toto-ets,
ceph rbd storage is always thin provisioned, even if the disktype is always raw.

To avoid space conflicts, you can set quotas on the rbd pool.

Code:
ceph osd pool set-quota <pool-name> [max_objects <obj-count>] [max_bytes <bytes>]
should do the job, if I correctly remember.
 
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Hi, thanks for the info. Could you explain to me in detail exactly what thin provisioning means? Maybe it shows me the actual space it occupies, instead of showing me the total of what I set?