From: Zhiqiang Wang Date: Wed, 19 Aug 2015 03:43:13 +0000 (+0800) Subject: doc: add the description for min_read_recency_for_promote X-Git-Tag: v9.1.0~258^2~1 X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=de00f6d0df159d51bd9dcec6a111e47b04a97c96;p=ceph.git doc: add the description for min_read_recency_for_promote This cache tiering option is introduced in proxy read. Signed-off-by: Zhiqiang Wang --- diff --git a/doc/dev/cache-pool.rst b/doc/dev/cache-pool.rst index 5fa910f98355..718a2b325408 100644 --- a/doc/dev/cache-pool.rst +++ b/doc/dev/cache-pool.rst @@ -55,6 +55,7 @@ Set the target size and enable the tiering agent for foo-hot:: ceph osd pool set foo-hot hit_set_count 1 ceph osd pool set foo-hot hit_set_period 3600 # 1 hour ceph osd pool set foo-hot target_max_bytes 1000000000000 # 1 TB + ceph osd pool set foo-hot min_read_recency_for_promote 1 Drain the cache in preparation for turning it off:: @@ -112,6 +113,17 @@ evict cache objects, all hit_set_count HitSets are loaded into RAM. Currently there is minimal benefit for hit_set_count > 1 since the agent does not yet act intelligently on that information. +The ``min_read_recency_for_promote`` defines how many HitSets to check for the +existence of an object when handling a read operation. The checking result is +used to decide whether to promote the object asynchronously. Its value should be +between 0 and ``hit_set_count``. If it's set to 0, the object is always promoted. +If it's set to 1, the current HitSet is checked. And if this object is in the +current HitSet, it's promoted. Otherwise not. For the other values, the exact +number of archive HitSets are checked. The object is promoted if the object is +found in any of the most recent ``min_read_recency_for_promote`` HitSets. :: + + ceph osd pool set {cachepool} min_read_recency_for_promote 1 + Cache mode ~~~~~~~~~~ diff --git a/doc/rados/operations/cache-tiering.rst b/doc/rados/operations/cache-tiering.rst index 355d9369b6e9..e77137e7dc87 100644 --- a/doc/rados/operations/cache-tiering.rst +++ b/doc/rados/operations/cache-tiering.rst @@ -186,6 +186,17 @@ 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"). +The ``min_read_recency_for_promote`` defines how many HitSets to check for the +existence of an object when handling a read operation. The checking result is +used to decide whether to promote the object asynchronously. Its value should be +between 0 and ``hit_set_count``. If it's set to 0, the object is always promoted. +If it's set to 1, the current HitSet is checked. And if this object is in the +current HitSet, it's promoted. Otherwise not. For the other values, the exact +number of archive HitSets are checked. The object is promoted if the object is +found in any of the most recent ``min_read_recency_for_promote`` HitSets. :: + + ceph osd pool set {cachepool} min_read_recency_for_promote 1 + .. note:: The longer the period and the higher the count, 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