Hello all,
We have a ceph cluster with 72 OSDs distributed on 6 hosts, in 3 chassis. In our crush map the we are distributing the PGs on chassis (complete crush map below):
# rules
rule replicated_ruleset {
ruleset 0
type replicated
min_size 1
max_size 10
step take default
step chooseleaf firstn 0 type chassis
step emit
}
We had a host failure, and I can see that ceph is using 2 OSDs from the same chassis for a lot of the remapped PGs. Even worse, I can see that there are cases when a PG is using two OSDs from the same host like here:
3.5f6 37 0 4 37 0 149446656 3040 3040 active+remapped 2017-05-26 11:29:23.122820 61820'222074 61820:158025 [52,39] 52 [52,39,3] 52 61488'198356 2017-05-23 23:51:56.210597 61488'198356 2017-05-23 23:51:56.210597
I have tis in the log:
2017-05-26 11:26:53.244424 osd.52 10.12.193.69:6801/7044 1510 : cluster [INF] 3.5f6 restarting backfill on osd.39 from (0'0,0'0] MAX to 61488'203000
What can be wrong?
Our crush map looks like this:
# begin crush map
tunable choose_local_tries 0
tunable choose_local_fallback_tries 0
tunable choose_total_tries 50
tunable chooseleaf_descend_once 1
tunable straw_calc_version 1
# devices
device 0 osd.0
device 1 osd.1
device 2 osd.2
device 3 osd.3
....
device 69 osd.69
device 70 osd.70
device 71 osd.71
# types
type 0 osd
type 1 host
type 2 chassis
type 3 rack
type 4 row
type 5 pdu
type 6 pod
type 7 room
type 8 datacenter
type 9 region
type 10 root
# buckets
host tv-c1-al01 {
id -7 # do not change unnecessarily
# weight 21.840
alg straw
hash 0 # rjenkins1
item osd.5 weight 1.820
item osd.11 weight 1.820
item osd.17 weight 1.820
item osd.23 weight 1.820
item osd.29 weight 1.820
item osd.35 weight 1.820
item osd.41 weight 1.820
item osd.47 weight 1.820
item osd.53 weight 1.820
item osd.59 weight 1.820
item osd.65 weight 1.820
item osd.71 weight 1.820
}
host tv-c1-al02 {
id -3 # do not change unnecessarily
# weight 21.840
alg straw
hash 0 # rjenkins1
item osd.1 weight 1.820
item osd.7 weight 1.820
item osd.13 weight 1.820
item osd.19 weight 1.820
item osd.25 weight 1.820
item osd.31 weight 1.820
item osd.37 weight 1.820
item osd.43 weight 1.820
item osd.49 weight 1.820
item osd.55 weight 1.820
item osd.61 weight 1.820
item osd.67 weight 1.820
}
chassis tv-c1 {
id -8 # do not change unnecessarily
# weight 43.680
alg straw
hash 0 # rjenkins1
item tv-c1-al01 weight 21.840
item tv-c1-al02 weight 21.840
}
host tv-c2-al01 {
id -5 # do not change unnecessarily
# weight 21.840
alg straw
hash 0 # rjenkins1
item osd.3 weight 1.820
item osd.9 weight 1.820
item osd.15 weight 1.820
item osd.21 weight 1.820
item osd.27 weight 1.820
item osd.33 weight 1.820
item osd.39 weight 1.820
item osd.45 weight 1.820
item osd.51 weight 1.820
item osd.57 weight 1.820
item osd.63 weight 1.820
item osd.70 weight 1.820
}
host tv-c2-al02 {
id -2 # do not change unnecessarily
# weight 21.840
alg straw
hash 0 # rjenkins1
item osd.0 weight 1.820
item osd.6 weight 1.820
item osd.12 weight 1.820
item osd.18 weight 1.820
item osd.24 weight 1.820
item osd.30 weight 1.820
item osd.36 weight 1.820
item osd.42 weight 1.820
item osd.48 weight 1.820
item osd.54 weight 1.820
item osd.60 weight 1.820
item osd.66 weight 1.820
}
chassis tv-c2 {
id -9 # do not change unnecessarily
# weight 43.680
alg straw
hash 0 # rjenkins1
item tv-c2-al01 weight 21.840
item tv-c2-al02 weight 21.840
}
host tv-c1-al03 {
id -6 # do not change unnecessarily
# weight 21.840
alg straw
hash 0 # rjenkins1
item osd.4 weight 1.820
item osd.10 weight 1.820
item osd.16 weight 1.820
item osd.22 weight 1.820
item osd.28 weight 1.820
item osd.34 weight 1.820
item osd.40 weight 1.820
item osd.46 weight 1.820
item osd.52 weight 1.820
item osd.58 weight 1.820
item osd.64 weight 1.820
item osd.69 weight 1.820
}
host tv-c2-al03 {
id -4 # do not change unnecessarily
# weight 21.840
alg straw
hash 0 # rjenkins1
item osd.2 weight 1.820
item osd.8 weight 1.820
item osd.14 weight 1.820
item osd.20 weight 1.820
item osd.26 weight 1.820
item osd.32 weight 1.820
item osd.38 weight 1.820
item osd.44 weight 1.820
item osd.50 weight 1.820
item osd.56 weight 1.820
item osd.62 weight 1.820
item osd.68 weight 1.820
}
chassis tv-c3 {
id -10 # do not change unnecessarily
# weight 43.680
alg straw
hash 0 # rjenkins1
item tv-c1-al03 weight 21.840
item tv-c2-al03 weight 21.840
}
root default {
id -1 # do not change unnecessarily
# weight 131.040
alg straw
hash 0 # rjenkins1
item tv-c1 weight 43.680
item tv-c2 weight 43.680
item tv-c3 weight 43.680
}
# rules
rule replicated_ruleset {
ruleset 0
type replicated
min_size 1
max_size 10
step take default
step chooseleaf firstn 0 type chassis
step emit
}
# end crush map
Thank you,
Laszlo
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