$ crushtool --test -i crushmap --rule 0 --show-mappings --min-x 0 --max-x 10 --num-rep 2
CRUSH rule 0 x 0 [0,12]
CRUSH rule 0 x 1 [5,24]
CRUSH rule 0 x 2 [9,14]
CRUSH rule 0 x 3 [30,11]
CRUSH rule 0 x 4 [20,10]
CRUSH rule 0 x 5 [28,0]
CRUSH rule 0 x 6 [6,34]
CRUSH rule 0 x 7 [19,31]
CRUSH rule 0 x 8 [17,26]
CRUSH rule 0 x 9 [9,20]
CRUSH rule 0 x 10 [10,33]
crushtool --test -i crushmap --rule 0 --show-mappings --min-x 0 --max-x 10 --num-rep 3
CRUSH rule 0 x 0 [0,12,32]
CRUSH rule 0 x 1 [5,24,20]
CRUSH rule 0 x 2 [9,14,28]
CRUSH rule 0 x 3 [30,11,13]
CRUSH rule 0 x 4 [20,10,31]
CRUSH rule 0 x 5 [28,0,12]
CRUSH rule 0 x 6 [6,34,14]
CRUSH rule 0 x 7 [19,31,6]
CRUSH rule 0 x 8 [17,26,5]
CRUSH rule 0 x 9 [9,20,30]
CRUSH rule 0 x 10 [10,33,12]
In general it’s going well. But in some cases it could be better to test.
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In some cases, some operations may take a little longer to be processed by the osd. And the operation may fail, or even make the OSD to suicide.
There are many parameters for these timeouts. Some examples :
Thread suicide timed out
123
heartbeat_map is_healthy 'OSD::osd_op_tp thread 0x7f1ee3ca7700' had suicide timed out after 150
common/HeartbeatMap.cc: In function 'bool ceph::HeartbeatMap::_check(ceph::heartbeat_handle_d*, const char*, time_t)' thread 7f1f0c2a3700 time 2017-03-03 11:03:46.550118
common/HeartbeatMap.cc: 79: FAILED assert(0 == "hit suicide timeout")
花猫破解版
12
花猫破解osd_op_thread_suicide_timeout = 900
Operation thread timeout
1
heartbeat_map is_healthy 'OSD::osd_op_tp thread 0x7fd306416700' had timed out after 15
12
ceph tell osd.XX injectargs --osd-op-thread-timeout 90
(default value is 15s)
Recovery thread timout
1
heartbeat_map is_healthy 'OSD::recovery_tp thread 0x7f4c2edab700' had timed out after 30
Erasure code is rather designed for clusters with a sufficient size. However if you want to use it with a small amount of hosts you can also adapt the crushmap for a better matching distribution to your need.
Here a first example for distributing data with 1 host OR 2 drive fault tolerance with k=4, m=2 on 3 hosts and more.
12345678910
rule erasure_ruleset {
ruleset X
type erasure
花猫破解版 max_size 6
step take default
step choose indep 3 type host
step choose indep 2 type osd
step emit
}
rule replicated_ruleset {
ruleset X
type replicated
花猫破解版 max_size 3
step take default
step choose firstn 2 type datacenter
step chooseleaf firstn -1 type host
step emit
}
This working well with pool size=2 (not recommended!) or 3.
If you set pool size more than 3 (and increase the max_size in crush), be careful : you will have n-1 replica on one side and only one on the other datacenter.
If you want to be able to write data even when one of the datacenters is inaccessible, pool min_size should be set at 1 even if size is set to 3. In this case, pay attention to the monitors location.
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Aaahhh full disk this morning.
Sometimes the logs can go crazy, and the files can quickly reach several gigabytes.