mirror of
https://github.com/ceph/ceph
synced 2025-02-06 10:23:52 +00:00
4fcab2e7fc
Signed-off-by: Laura Flores <lflores@redhat.com> Co-authored-by: Josh Salomon <josh.salomon@gmail.com>
65 lines
2.3 KiB
ReStructuredText
65 lines
2.3 KiB
ReStructuredText
.. _read_balancer:
|
|
|
|
=======================================
|
|
Operating the Read (Primary) Balancer
|
|
=======================================
|
|
|
|
You might be wondering: How can I improve performance in my Ceph cluster?
|
|
One important data point you can check is the ``read_balance_score`` on each
|
|
of your replicated pools.
|
|
|
|
This metric, available via ``ceph osd pool ls detail`` (see :ref:`rados_pools`
|
|
for more details) indicates read performance, or how balanced the primaries are
|
|
for each replicated pool. In most cases, if a ``read_balance_score`` is above 1
|
|
(for instance, 1.5), this means that your pool has unbalanced primaries and that
|
|
you may want to try improving your read performance with the read balancer.
|
|
|
|
Online Optimization
|
|
===================
|
|
|
|
At present, there is no online option for the read balancer. However, we plan to add
|
|
the read balancer as an option to the :ref:`balancer` in the next Ceph version
|
|
so it can be enabled to run automatically in the background like the upmap balancer.
|
|
|
|
Offline Optimization
|
|
====================
|
|
|
|
Primaries are updated with an offline optimizer that is built into the
|
|
:ref:`osdmaptool`.
|
|
|
|
#. Grab the latest copy of your osdmap:
|
|
|
|
.. prompt:: bash $
|
|
|
|
ceph osd getmap -o om
|
|
|
|
#. Run the optimizer:
|
|
|
|
.. prompt:: bash $
|
|
|
|
osdmaptool om --read out.txt --read-pool <pool name> [--vstart]
|
|
|
|
It is highly recommended that you run the capacity balancer before running the
|
|
balancer to ensure optimal results. See :ref:`upmap` for details on how to balance
|
|
capacity in a cluster.
|
|
|
|
#. Apply the changes:
|
|
|
|
.. prompt:: bash $
|
|
|
|
source out.txt
|
|
|
|
In the above example, the proposed changes are written to the output file
|
|
``out.txt``. The commands in this procedure are normal Ceph CLI commands
|
|
that can be run in order to apply the changes to the cluster.
|
|
|
|
If you are working in a vstart cluster, you may pass the ``--vstart`` parameter
|
|
as shown above so the CLI commands are formatted with the `./bin/` prefix.
|
|
|
|
Note that any time the number of pgs changes (for instance, if the pg autoscaler [:ref:`pg-autoscaler`]
|
|
kicks in), you should consider rechecking the scores and rerunning the balancer if needed.
|
|
|
|
To see some details about what the tool is doing, you can pass
|
|
``--debug-osd 10`` to ``osdmaptool``. To see even more details, pass
|
|
``--debug-osd 20`` to ``osdmaptool``.
|