mirror of
https://github.com/ceph/ceph
synced 2024-12-29 06:52:35 +00:00
43 lines
1.4 KiB
ReStructuredText
43 lines
1.4 KiB
ReStructuredText
===================
|
|
RBD Replay
|
|
===================
|
|
|
|
.. 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 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 the trace. Make sure to capture ``pthread_id`` context::
|
|
|
|
mkdir -p traces
|
|
lttng create -o traces librbd
|
|
lttng enable-event -u 'librbd:*'
|
|
lttng add-context -u -t pthread_id
|
|
lttng start
|
|
# run RBD workload here
|
|
lttng stop
|
|
|
|
#. Process the trace with `rbd-replay-prep`_::
|
|
|
|
rbd-replay-prep traces/ust/uid/*/* replay.bin
|
|
|
|
#. 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.
|
|
|
|
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
|