On 05/21/2014 03:29 PM, Vilobh Meshram wrote: > Hi All, > > I want to understand on how do CEPH users go about Quota Management when > CEPH is used with Openstack. > > 1. Is it recommended to use a common pool say ?volumes? for creating > volumes which is shared by all tenants ? In this case a common > keyring ceph.common.keyring will be shared across all the > tenants/common volume pool. Yes, using a common pool is recommended. More pools take up more cpu and memory on the osds, since placement groups (shards of pools) are the unit of recovery. Having a pool per tenant would be a scaling issue. There is a further level of division in rados called a 'namespace', which can provide finer-grained cephx security within a pool, but rbd does not support it yet, and as it stands it would not be useful for quotas [1]. > 2. Or is it recommended to use a pool for each tenant say ?volume1 pool > for tenant1? , ?volume2 pool for tenant2" ? In this case we will > have a keyring per volume pool/ tenant I.e. Keyring 1 for > volume/tenant1 and so on. > > Considering both of these cases how do we guarantee that we enforce a > quota for each user inside a tenant say a quota of say 5 volumes to be > created by each user. When using OpenStack, Cinder does the quota management for volumes based on its database, and can limit total space, number of volumes and number of snapshots [2]. RBD is entirely unaware of OpenStack tenants. Josh [1] http://wiki.ceph.com/Planning/Sideboard/rbd%3A_namespace_support [2] http://docs.openstack.org/user-guide-admin/content/cli_set_quotas.html#cli_set_block_storage_quotas
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