Monthly Archives: February 2014

How does a Ceph OSD handle a read message ? (in Firefly and up)

When an OSD handles an operation it is queued to a PG, it is added to the op_wq work queue ( or to the waiting_for_map list if the queue_op method of PG finds that it must wait for an OSDMap … Continue reading

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figuring out why ccache misses

When compiling Ceph, ccache may appear to miss more than expected, as shown by the cache miss line of ccache -s cache directory /home/loic/.ccache cache hit (direct) 1 cache hit (preprocessed) 0 cache miss 1 files in cache 3 cache … Continue reading

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Ceph paxos propose interval

When a command is sent to the Ceph monitor, such as ceph osd pool create, it will add a pool to the pending changes of the maps. The modification is stashed for paxos propose interval seconds before it is used … Continue reading

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