update ceph source to reef 18.2.1

[ceph.git] / ceph / doc / rados / configuration / osd-config-ref.rst

diff --git a/ceph/doc/rados/configuration/osd-config-ref.rst b/ceph/doc/rados/configuration/osd-config-ref.rst
index 3c3b378e7b4ef2afbc7b5e48886af0a439788935..0601212008383f0ec0f3841df84178788c438938 100644 (file)
--- a/ceph/doc/rados/configuration/osd-config-ref.rst
+++ b/ceph/doc/rados/configuration/osd-config-ref.rst
@@ -145,17 +145,20 @@ See `Pool & PG Config Reference`_ for details.
 Scrubbing
 =========
 
-In addition to making multiple copies of objects, Ceph ensures data integrity by
-scrubbing placement groups. Ceph scrubbing is analogous to ``fsck`` on the
-object storage layer. For each placement group, Ceph generates a catalog of all
-objects and compares each primary object and its replicas to ensure that no
-objects are missing or mismatched. Light scrubbing (daily) checks the object
-size and attributes.  Deep scrubbing (weekly) reads the data and uses checksums
-to ensure data integrity.
-
-Scrubbing is important for maintaining data integrity, but it can reduce
-performance. You can adjust the following settings to increase or decrease
-scrubbing operations.
+One way that Ceph ensures data integrity is by "scrubbing" placement groups.
+Ceph scrubbing is analogous to ``fsck`` on the object storage layer. Ceph
+generates a catalog of all objects in each placement group and compares each
+primary object to its replicas, ensuring that no objects are missing or
+mismatched. Light scrubbing checks the object size and attributes, and is
+usually done daily. Deep scrubbing reads the data and uses checksums to ensure
+data integrity, and is usually done weekly. The freqeuncies of both light
+scrubbing and deep scrubbing are determined by the cluster's configuration,
+which is fully under your control and subject to the settings explained below
+in this section.
+
+Although scrubbing is important for maintaining data integrity, it can reduce
+the performance of the Ceph cluster. You can adjust the following settings to
+increase or decrease the frequency and depth of scrubbing operations.
 
 
 .. confval:: osd_max_scrubs