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IO Limits

Would like to request a feature to limit IOs on a per-LUN basis.

Basically, if an organization were to build a large PetaSAN cluster (scaling is what Ceph does best after all), and wanted to sublet it to different departments within the organization, those departments would be limited to space (the size of their LUNs) but that an option could also be enabled to limit IOPS to the LUN to prevent an org doing some IO heavy tasks from impacting IO performance to other departments using of the cluster.

I know my former employer (who wasn't using Ceph but who would be a good candidate for PetaSAN due to their vmware environment) had developers doing builds all the time, this would often impact performance for other users due to limited IOP resources available with the storage.

The ability to maybe do IO prioritization would also be good; so that if, for example, a backup job is running at 3AM and there is no competition for the resources, it can run wide open.

Thanks!

Yes that would be nice. Currently there is preliminary work to add Quality of Service to Ceph:

http://docs.ceph.com/docs/luminous/rados/configuration/osd-config-ref/#qos-based-on-mclock
https://www.spinics.net/lists/ceph-devel/msg39528.html

Once this has matured, we would add support to it.

Hi admin,

How can I control a user's IOP?

Or QoS for PetaSAN

You can do quality of service IOPS limitations on a per RBD basis right now with Red Hat Ceph from the dashboard, so there should be a way to do it via CLI. Strangely enough, I can't find anything just at a first glance however.

 

Edit: I spoke too soon! you can change your RBD QOS via  librbd heres a link, scroll to bottom!  https://people.redhat.com/bhubbard/nature/default/rbd/rbd-config-ref/