Hi everyone,
As a newbie, I am grateful for receiving many helps from people on
this mailing list. I would like to quickly test my understanding on
'step choose|chooseleaf' and wish you could point out any of my
mistakes.
Suppose I have a following topology:
root=default
|
datacenter=dc
/ | \
row=a row=b row=c
rack=a1 rack=b1 rack=c1
host=a1.1 host=b1.1 host=c1.1
host=a1.2 host=b1.2 host=c1.2
host=a1.3 host=b1.3 host=c1.3
rack=a2 rack=b2 rack=c2
host=a2.1 host=b2.1 host=c2.1
host=a2.2 host=b2.2 host=c2.2
host=a2.3 host=b2.3 host=c2.3
rack=a3 rack=b3 rack=c3
host=a3.1 host=b3.1 host=c3.1
host=a3.2 host=b3.2 host=c3.2
host=a3.3 host=b3.3 host=c3.3
*each host has 3 OSDs.
Then,
1) a rule that makes 3 replicas with a row-level failure domain would be like:
...
step take default
step chooseleaf fisrtn 0 type row
2) a rule that makes 3 replicas in different racks within the same row:
...
step take default
step choose firstn 1 type row
step chooseleaf firstn 0 type rack
3) a rule that makes 3+2 EC with a host-level failure domain:
...
step take default
step chooseleaf indep 0 type host
Are the above three rules correct regarding the usage of 'step
choose|chooseleaf'?
Thank you!
Regards,
Cody
Here are related references from the mailing list:
[1] http://lists.ceph.com/pipermail/ceph-users-ceph.com/2016-June/010370.html
[2] http://lists.ceph.com/pipermail/ceph-users-ceph.com/2018-August/029255.html
[3] http://lists.ceph.com/pipermail/ceph-users-ceph.com/2018-August/029148.html
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