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path: root/include/linux/crush/crush.h
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2013-01-17libceph: for chooseleaf rules, retry CRUSH map descent from root if leaf is ↵Jim Schutt
failed Add libceph support for a new CRUSH tunable recently added to Ceph servers. Consider the CRUSH rule step chooseleaf firstn 0 type <node_type> This rule means that <n> replicas will be chosen in a manner such that each chosen leaf's branch will contain a unique instance of <node_type>. When an object is re-replicated after a leaf failure, if the CRUSH map uses a chooseleaf rule the remapped replica ends up under the <node_type> bucket that held the failed leaf. This causes uneven data distribution across the storage cluster, to the point that when all the leaves but one fail under a particular <node_type> bucket, that remaining leaf holds all the data from its failed peers. This behavior also limits the number of peers that can participate in the re-replication of the data held by the failed leaf, which increases the time required to re-replicate after a failure. For a chooseleaf CRUSH rule, the tree descent has two steps: call them the inner and outer descents. If the tree descent down to <node_type> is the outer descent, and the descent from <node_type> down to a leaf is the inner descent, the issue is that a down leaf is detected on the inner descent, so only the inner descent is retried. In order to disperse re-replicated data as widely as possible across a storage cluster after a failure, we want to retry the outer descent. So, fix up crush_choose() to allow the inner descent to return immediately on choosing a failed leaf. Wire this up as a new CRUSH tunable. Note that after this change, for a chooseleaf rule, if the primary OSD in a placement group has failed, choosing a replacement may result in one of the other OSDs in the PG colliding with the new primary. This requires that OSD's data for that PG to need moving as well. This seems unavoidable but should be relatively rare. This corresponds to ceph.git commit 88f218181a9e6d2292e2697fc93797d0f6d6e5dc. Signed-off-by: Jim Schutt <jaschut@sandia.gov> Reviewed-by: Sage Weil <sage@inktank.com>
2012-07-31libceph: support crush tunablesSage Weil
The server side recently added support for tuning some magic crush variables. Decode these variables if they are present, or use the default values if they are not present. Corresponds to ceph.git commit 89af369c25f274fe62ef730e5e8aad0c54f1e5a5. Signed-off-by: caleb miles <caleb.miles@inktank.com> Reviewed-by: Sage Weil <sage@inktank.com> Reviewed-by: Alex Elder <elder@inktank.com> Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
2012-05-07crush: fix tree node weight lookupSage Weil
Fix the node weight lookup for tree buckets by using a correct accessor. Reflects ceph.git commit d287ade5bcbdca82a3aef145b92924cf1e856733. Reviewed-by: Alex Elder <elder@inktank.com> Signed-off-by: Sage Weil <sage@inktank.com>
2012-05-07crush: remove parent mapsSage Weil
These were used for the ill-fated forcefeed feature. Remove them. Reflects ceph.git commit ebdf80edfecfbd5a842b71fbe5732857994380c1. Reviewed-by: Alex Elder <elder@inktank.com> Signed-off-by: Sage Weil <sage@inktank.com>
2012-05-07crush: clean up types, const-nessSage Weil
Move various types from int -> __u32 (or similar), and add const as appropriate. This reflects changes that have been present in the userland implementation for some time. Reviewed-by: Alex Elder <elder@inktank.com> Signed-off-by: Sage Weil <sage@inktank.com>
2010-10-20ceph: factor out libceph from Ceph file systemYehuda Sadeh
This factors out protocol and low-level storage parts of ceph into a separate libceph module living in net/ceph and include/linux/ceph. This is mostly a matter of moving files around. However, a few key pieces of the interface change as well: - ceph_client becomes ceph_fs_client and ceph_client, where the latter captures the mon and osd clients, and the fs_client gets the mds client and file system specific pieces. - Mount option parsing and debugfs setup is correspondingly broken into two pieces. - The mon client gets a generic handler callback for otherwise unknown messages (mds map, in this case). - The basic supported/required feature bits can be expanded (and are by ceph_fs_client). No functional change, aside from some subtle error handling cases that got cleaned up in the refactoring process. Signed-off-by: Sage Weil <sage@newdream.net>