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doc: Reformatting on rbd replay doc.

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Signed-off-by: John Wilkins <john.wilkins@inktank.com>
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John Wilkins 2014-12-02 11:23:55 -08:00
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doc/rbd/rbd-replay.rst
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@ -4,13 +4,15 @@
.. index:: Ceph Block Device; RBD Replay
RBD Replay is a set of tools for capturing and replaying Rados Block Device (RBD) workloads.
To capture an RBD workload, ``lttng-tools`` must be installed on the client, and ``librbd`` on the clent must be the Giant release or later.
To replay an RBD workload, ``librbd`` on the clent must be the Giant release or later.
RBD Replay is a set of tools for capturing and replaying Rados Block Device
(RBD) workloads. To capture an RBD workload, ``lttng-tools`` must be installed
on the client, and ``librbd`` on the client must be the v0.87 (Giant) release
or later. To replay an RBD workload, ``librbd`` on the client must be the Giant
release or later.
Capture and replay takes three steps\:
Capture and replay takes three steps:
1) Capture the trace. Make sure to capture ``pthread_id`` context::
#. Capture the trace. Make sure to capture ``pthread_id`` context::
mkdir -p traces
lttng create -o traces librbd
@ -20,18 +22,21 @@ Capture and replay takes three steps\:
# run RBD workload here
lttng stop
2) Process the trace with `rbd-replay-prep`_::
#. Process the trace with `rbd-replay-prep`_::
rbd-replay-prep traces/ust/uid/*/* replay.bin
3) Replay the trace with `rbd-replay`_. Use read-only until you know it's doing what you want::
#. Replay the trace with `rbd-replay`_. Use read-only until you know
it's doing what you want::
rbd-replay --read-only replay.bin
.. important:: ``rbd-replay`` will destroy data by default. Do not use against an image you wish to keep, unless you use the ``--read-only`` option.
.. important:: ``rbd-replay`` will destroy data by default. Do not use against
an image you wish to keep, unless you use the ``--read-only`` option.
The replayed workload does not have to be against the same RBD image or even the same cluster as the captured workload.
To account for differences, you may need to use the ``--pool`` and ``--map-image`` options of ``rbd-replay``.
The replayed workload does not have to be against the same RBD image or even the
same cluster as the captured workload. To account for differences, you may need
to use the ``--pool`` and ``--map-image`` options of ``rbd-replay``.
.. _rbd-replay: ../../man/8/rbd-replay
.. _rbd-replay-prep: ../../man/8/rbd-replay-prep