CRUSH only specifies where the chunks are placed, not how many chunks there are (the pool specifies this)
This is the same with replicated rules: pool specifies the number of replicas, the rule where they are put.
You can use one CRUSH rule for multiple ec pools
Paul
--
Paul Emmerich
Looking for help with your Ceph cluster? Contact us at https://croit.io
croit GmbH
Freseniusstr. 31h
81247 München
www.croit.io
Tel: +49 89 1896585 90
Paul Emmerich
Looking for help with your Ceph cluster? Contact us at https://croit.io
croit GmbH
Freseniusstr. 31h
81247 München
www.croit.io
Tel: +49 89 1896585 90
On Wed, May 22, 2019 at 3:03 PM Rainer Krienke <krienke@xxxxxxxxxxxxxx> wrote:
Hello,
I created an erasure code profile named ecprofile-42 with the following
parameters:
$ ceph osd erasure-code-profile set ecprofile-42 plugin=jerasure k=4 m=2
Next I created a new pool using the ec profile from above:
$ ceph osd pool create my_erasure_pool 64 64 erasure ecprofile-42
The pool created then has an autogenerated crush rule with the contents
as shown at the end of this mail (see: ceph osd crush rule dump
my_erasure_pool).
What I am missing in the output of the crush rule dump below are the k,m
values used for this pool or a "link" from the crushrule to the erasure
code profile that contains these settings and was used creating the pool
and thus the ec crushrule. If I had several ec profiles and pools
created with the different ec profiles how else could I see which k,m
values were used for the different pools?
For a replicated crush rule there is the size parameter which is part of
the crush-rule and indirectly tells you the number of replicas, but what
about erasure coded pools?
Probably there is somewhere the link I am looking for, but I din't find
it yet...
Thanks Rainer
#
# autogenerated crush rule my_erasure_pool:
#
$ ceph osd crush rule dump my_erasure_pool
{
"rule_id": 1,
"rule_name": "my_erasure_pool",
"ruleset": 1,
"type": 3,
"min_size": 3,
"max_size": 6,
"steps": [
{
"op": "set_chooseleaf_tries",
"num": 5
},
{
"op": "set_choose_tries",
"num": 100
},
{
"op": "take",
"item": -1,
"item_name": "default"
},
{
"op": "chooseleaf_indep",
"num": 0,
"type": "host"
},
{
"op": "emit"
}
]
}
--
Rainer Krienke, Uni Koblenz, Rechenzentrum, A22, Universitaetsstrasse 1
56070 Koblenz, Tel: +49261287 1312 Fax +49261287 100 1312
Web: http://userpages.uni-koblenz.de/~krienke
PGP: http://userpages.uni-koblenz.de/~krienke/mypgp.html
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