solid-state drives). For filestore with filestore_punch_hole = false, the
recommended setting is image object size (typically 4M).
+* crush_location=x - Specify the location of the client in terms of CRUSH
+ hierarchy (since 5.8). This is a set of key-value pairs separated from
+ each other by '|', with keys separated from values by ':'. Note that '|'
+ may need to be quoted or escaped to avoid it being interpreted as a pipe
+ by the shell. The key is the bucket type name (e.g. rack, datacenter or
+ region with default bucket types) and the value is the bucket name. For
+ example, to indicate that the client is local to rack "myrack", data center
+ "mydc" and region "myregion"::
+
+ crush_location=rack:myrack|datacenter:mydc|region:myregion
+
+ Each key-value pair stands on its own: "myrack" doesn't need to reside in
+ "mydc", which in turn doesn't need to reside in "myregion". The location
+ is not a path to the root of the hierarchy but rather a set of nodes that
+ are matched independently, owning to the fact that bucket names are unique
+ within a CRUSH map. "Multipath" locations are supported, so it is possible
+ to indicate locality for multiple parallel hierarchies::
+
+ crush_location=rack:myrack1|rack:myrack2|datacenter:mydc
+
+* read_from_replica=no - Disable replica reads, always pick the primary OSD
+ (since 5.8, default).
+
+* read_from_replica=balance - When issued a read on a replicated pool, pick
+ a random OSD for serving it (since 5.8).
+
+ This mode is safe for general use only since Octopus (i.e. after "ceph osd
+ require-osd-release octopus"). Otherwise it should be limited to read-only
+ workloads such as images mapped read-only everywhere or snapshots.
+
+* read_from_replica=localize - When issued a read on a replicated pool, pick
+ the most local OSD for serving it (since 5.8). The locality metric is
+ calculated against the location of the client given with crush_location;
+ a match with the lowest-valued bucket type wins. For example, with default
+ bucket types, an OSD in a matching rack is closer than an OSD in a matching
+ data center, which in turn is closer than an OSD in a matching region.
+
+ This mode is safe for general use only since Octopus (i.e. after "ceph osd
+ require-osd-release octopus"). Otherwise it should be limited to read-only
+ workloads such as images mapped read-only everywhere or snapshots.
+
+* compression_hint=none - Don't set compression hints (since 5.8, default).
+
+* compression_hint=compressible - Hint to the underlying OSD object store
+ backend that the data is compressible, enabling compression in passive mode
+ (since 5.8).
+
+* compression_hint=incompressible - Hint to the underlying OSD object store
+ backend that the data is incompressible, disabling compression in aggressive
+ mode (since 5.8).
+
`rbd device unmap` options:
* force - Force the unmapping of a block device that is open (since 4.9). The