====== CEPH performance monitoring ======

===== basic info =====

==== ceph ====

<code bash>
ceph -s
ceph -w
ceph df
ceph osd tree
ceph osd df tree
</code>

==== rados ====

<code>
rados df
</code>
Where:
  * **USED COMPR**: amount of space allocated for compressed data (i.e. this includes comrpessed data plus all the allocation, replication and erasure coding overhead).
  * **UNDER COMPR**: amount of data passed through compression (summed over all replicas) and beneficial enough to be stored in a compressed form.

==== RBD Rados Block Device ====
<code>
rbd ls
rbd du
</code>
==== perf ====

<code bash>
ceph iostat

ceph osd perf

rbd perf image iostat  # and wait 30 sec
rbd perf image iotop   # and wait 30 sec

rbd du
</code>


https://ceph.io/community/new-mimic-iostat-plugin/

==== rados benchmark ====
Hints from [[https://yourcmc.ru/wiki/Ceph_performance#Test_your_Ceph_cluster]]:
  * Don't use `rados bench`. It creates a small number of objects (1-2 for a thread) so all of them always reside in cache and improve the results far beyond they should be.
  * You can use `rbd bench`, but fio is better.

<code bash>
ceph osd pool create test
rados -p test bench 10 write --no-cleanup
rados -p test bench 10 seq
rados -p test bench -t 4 10 seq
rados -p test bench 10 rand

rados bench -p test 60 write -b 4M -t 16 --no-cleanup
rados bench -p test 60 seq -t 16
rados bench -p test 60 rand -t 16

rados -p test cleanup
</code>



==== rbd benchmark ====

[[https://access.redhat.com/documentation/en-us/red_hat_ceph_storage/1.3/html/administration_guide/benchmarking_performance#block_device|Chapter 9. Benchmarking Performance]]

<code bash>
# Image 1G:
rbd create test/myimage --size 1024

#TBD ... 
#rbd device map test/myimage --cluster 
#rbd device unmap /dev/rbdX

rbd rm test/myimage
</code>