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Feature #26975

Rados level IO priority for OSD operations

Added by Марк Коренберг 4 months ago. Updated 4 months ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
-
Target version:
Start date:
08/21/2018
Due date:
% Done:

0%

Source:
Community (dev)
Tags:
Backport:
Reviewed:
Component(RADOS):
Pull request ID:

Description

What I mean:

Suppose busy Ceph cluster.

Every OSD has many IO requests from clients in it's queue. Today, all requests have the same priority. Usually MDS requests should have priority over, say, RBD IOs since these IO may block whole FS. Another example is IO from one RBD image over another RBD image. Or, priority of IO on one Rados pool over another pool.

Sure, these priorities should be tunable in some way, but these priorities should be first implemented at Rados level.

History

#1 Updated by Марк Коренберг 4 months ago

For "Rados level" I mean librados API at least, and implementation in OSD too.

#2 Updated by Greg Farnum 4 months ago

  • Project changed from Ceph to RADOS
  • Category deleted (librados)

Do note that
1) "Messages" can already have priority, although its utility at this point is quite limited it's not totally useless.
2) This is part of a comprehensive QoS solution, and the ongoing dmclock work is our attempt to fulfill such needs.

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