Question about xattr and subvolumes
Hi, I'm installing a new instance (my first) of Ceph. Our cluster runs AlmaLinux9 + Quincy. Now I'm dealing with CephFS and quotas. I read documentation about setting up quotas with virtual attributes (xattr) and creating volumes and subvolumes with a prefixed size. I cannot distinguish which is the best option for us. Currently we create a directory with a project name and some subdirectories inside. I would like to understand the difference between both options. Thanks in advance. -- Dario Graña PIC (Port d'Informació Científica) Campus UAB, Edificio D E-08193 Bellaterra, Barcelona http://www.pic.es Avis - Aviso - Legal Notice: http://legal.ifae.es
On Tue, Jun 6, 2023 at 4:30 PM Dario Graña <dgrana@pic.es> wrote:
Hi,
I'm installing a new instance (my first) of Ceph. Our cluster runs AlmaLinux9 + Quincy. Now I'm dealing with CephFS and quotas. I read documentation about setting up quotas with virtual attributes (xattr) and creating volumes and subvolumes with a prefixed size. I cannot distinguish which is the best option for us.
Creating a volume would create a fs and subvolumes are essentially directories inside the fs which are managed through mgr subvolume APIs. The subvolumes are introduced for openstack and openshift use case which expect these subvolumes to be programmatically managed via APIs. Answering the quota question, in cephfs, quota is set using the virtual xattr. The subvolume creation with size essentially uses the same virtual xattr interface to set the quota size.
Currently we create a directory with a project name and some subdirectories inside.
You can explore subvolumegroup and subvolume mgr APIs if it fits your use case. Please note that it's mainly designed for openstack/openshift kind of use cases where each subvolume is per PVC and the data distinction is maintained e.g., there won't be hardlinks created across the subvolumes.
I would like to understand the difference between both options.
Thanks in advance.
-- Dario Graña PIC (Port d'Informació Científica) Campus UAB, Edificio D E-08193 Bellaterra, Barcelona http://www.pic.es Avis - Aviso - Legal Notice: http://legal.ifae.es _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io
Thank you for the answer, that's what I was looking for! On Wed, Jun 7, 2023 at 7:59 AM Kotresh Hiremath Ravishankar < khiremat@redhat.com> wrote:
On Tue, Jun 6, 2023 at 4:30 PM Dario Graña <dgrana@pic.es> wrote:
Hi,
I'm installing a new instance (my first) of Ceph. Our cluster runs AlmaLinux9 + Quincy. Now I'm dealing with CephFS and quotas. I read documentation about setting up quotas with virtual attributes (xattr) and creating volumes and subvolumes with a prefixed size. I cannot distinguish which is the best option for us.
Creating a volume would create a fs and subvolumes are essentially directories inside the fs which are managed through mgr subvolume APIs. The subvolumes are introduced for openstack and openshift use case which expect these subvolumes to be programmatically managed via APIs.
Answering the quota question, in cephfs, quota is set using the virtual xattr. The subvolume creation with size essentially uses the same virtual xattr interface to set the quota size.
Currently we create a directory with a project name and some subdirectories inside.
You can explore subvolumegroup and subvolume mgr APIs if it fits your use case. Please note that it's mainly designed for openstack/openshift kind of use cases where each subvolume is per PVC and the data distinction is maintained e.g., there won't be hardlinks created across the subvolumes.
I would like to understand the difference between both options.
Thanks in advance.
-- Dario Graña PIC (Port d'Informació Científica) Campus UAB, Edificio D E-08193 Bellaterra, Barcelona http://www.pic.es Avis - Aviso - Legal Notice: http://legal.ifae.es _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io
participants (2)
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Dario Graña
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Kotresh Hiremath Ravishankar