ceph/doc/rados/operations
Loic Dachary 9c825ec2c4 documentation: revise placement group number guide
When a cluster has few OSDs (less than 50) propose a preselection of
values: as long as the number of placement groups is not too small nor
too large, it won't make much of a difference anyway.

Users of small clusters tend to blindly apply the (OSD*100)/(pool size)
formula and worry about chosing a wrong value because they do not
understand the tradeoffs. The preselection will hopefully save them from
this uncertainty.

Add an explanation of how placement groups relate to OSDs, CRUSH and
pools to help understand the tradeoffs. Explain the
tradeoffs (durability, distribution and resource usages) with examples.

Signed-off-by: Loic Dachary <loic-201408@dachary.org>
Reviewed-by: Gerben Meijer <infernix@gmail.com>
Reviewed-by: Laurent Guerby <laurent@guerby.net>
2014-09-23 16:54:50 +02:00
..
add-or-rm-mons.rst
add-or-rm-osds.rst doc: Fixed broken hyperlink. 2014-09-16 11:28:19 -07:00
cache-tiering.rst
control.rst documentation: explain ceph osd reweight vs crush weight 2014-09-19 17:19:41 +02:00
crush-map.rst doc: Added bucket management commands to ops/crush-map 2014-09-14 10:41:16 -04:00
data-placement.rst
erasure-code-isa.rst documentation: isa plugin is sub section of erasure code profile 2014-09-14 01:01:51 +02:00
erasure-code-jerasure.rst documentation: jerasure plugin is sub section of erasure code profile 2014-09-14 01:01:51 +02:00
erasure-code-lrc.rst erasure-code: lowercase LRC plugin name 2014-08-31 12:51:03 +02:00
erasure-code-profile.rst documentation: erasure code profile update 2014-09-14 01:01:21 +02:00
index.rst documentation: erasure code profile update 2014-09-14 01:01:21 +02:00
monitoring-osd-pg.rst
monitoring.rst
operating.rst doc: Removed Debian reference from Upstart. 2014-08-07 15:30:43 -07:00
pg-concepts.rst
pg-states.rst
placement-groups.rst documentation: revise placement group number guide 2014-09-23 16:54:50 +02:00
pools.rst documentation: erasure code profile update 2014-09-14 01:01:21 +02:00
user-management.rst doc: Provided additional detail on daemon-specific caps syntax. 2014-09-02 11:38:16 -07:00