From: Sage Weil Date: Fri, 13 May 2016 14:27:31 +0000 (-0400) Subject: doc/rados: adjust example cache tiering settings X-Git-Tag: v11.0.0~562^2 X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F9070%2Fhead;p=ceph.git doc/rados: adjust example cache tiering settings These are saner values. Signed-off-by: Sage Weil --- diff --git a/doc/rados/operations/cache-tiering.rst b/doc/rados/operations/cache-tiering.rst index 1fa3201f5f72..322c6ff48956 100644 --- a/doc/rados/operations/cache-tiering.rst +++ b/doc/rados/operations/cache-tiering.rst @@ -238,10 +238,13 @@ For example:: The ``hit_set_count`` and ``hit_set_period`` define how much time each HitSet should cover, and how many such HitSets to store. :: - ceph osd pool set {cachepool} hit_set_count 1 - ceph osd pool set {cachepool} hit_set_period 3600 + ceph osd pool set {cachepool} hit_set_count 12 + ceph osd pool set {cachepool} hit_set_period 14400 ceph osd pool set {cachepool} target_max_bytes 1000000000000 +.. note:: A larger ``hit_set_count`` results in more RAM consumed by + the ``ceph-osd`` process. + Binning accesses over time allows Ceph to determine whether a Ceph client accessed an object at least once, or more than once over a time period ("age" vs "temperature"). @@ -258,13 +261,14 @@ found in any of the most recent ``min_read_recency_for_promote`` HitSets. A similar parameter can be set for the write operation, which is ``min_write_recency_for_promote``. :: - ceph osd pool set {cachepool} min_read_recency_for_promote 1 - ceph osd pool set {cachepool} min_write_recency_for_promote 1 + ceph osd pool set {cachepool} min_read_recency_for_promote 2 + ceph osd pool set {cachepool} min_write_recency_for_promote 2 .. note:: The longer the period and the higher the - ``min_read_recency_for_promote``/``min_write_recency_for_promote``, the more - RAM the ``ceph-osd`` daemon consumes. In particular, when the agent is active - to flush or evict cache objects, all ``hit_set_count`` HitSets are loaded + ``min_read_recency_for_promote`` and + ``min_write_recency_for_promote``values, the more RAM the ``ceph-osd`` + daemon consumes. In particular, when the agent is active to flush + or evict cache objects, all ``hit_set_count`` HitSets are loaded into RAM.