Tim Gipson
2018-02-08 20:43:21 UTC
Hey all,
We are trying to get an erasure coding cluster up and running but we are having a problem getting the cluster to remain up if we lose an OSD host.
Currently we have 6 OSD hosts with 6 OSDs a piece. I'm trying to build an EC profile and a crush rule that will allow the cluster to continue running if we lose a host, but I seem to misunderstand how the configuration of an EC pool/cluster is supposed to be implemented. I would like to be able to set this up to allow for 2 host failures before data loss occurs.
Here is my crush rule:
{
"rule_id": 2,
"rule_name": "EC_ENA",
"ruleset": 2,
"type": 3,
"min_size": 6,
"max_size": 8,
"steps": [
{
"op": "take",
"item": -1,
"item_name": "default"
},
{
"op": "choose_indep",
"num": 4,
"type": "host"
},
{
"op": "choose_indep",
"num": 2,
"type": "osd"
},
{
"op": "emit"
}
]
}
Here is my EC profile:
crush-device-class=
crush-failure-domain=host
crush-root=default
jerasure-per-chunk-alignment=false
k=6
m=2
plugin=jerasure
technique=reed_sol_van
w=8
Any direction or help would be greatly appreciated.
Thanks,
Tim Gipson
Systems Engineer
We are trying to get an erasure coding cluster up and running but we are having a problem getting the cluster to remain up if we lose an OSD host.
Currently we have 6 OSD hosts with 6 OSDs a piece. I'm trying to build an EC profile and a crush rule that will allow the cluster to continue running if we lose a host, but I seem to misunderstand how the configuration of an EC pool/cluster is supposed to be implemented. I would like to be able to set this up to allow for 2 host failures before data loss occurs.
Here is my crush rule:
{
"rule_id": 2,
"rule_name": "EC_ENA",
"ruleset": 2,
"type": 3,
"min_size": 6,
"max_size": 8,
"steps": [
{
"op": "take",
"item": -1,
"item_name": "default"
},
{
"op": "choose_indep",
"num": 4,
"type": "host"
},
{
"op": "choose_indep",
"num": 2,
"type": "osd"
},
{
"op": "emit"
}
]
}
Here is my EC profile:
crush-device-class=
crush-failure-domain=host
crush-root=default
jerasure-per-chunk-alignment=false
k=6
m=2
plugin=jerasure
technique=reed_sol_van
w=8
Any direction or help would be greatly appreciated.
Thanks,
Tim Gipson
Systems Engineer