这篇文章主要介绍ceph隔离级别的示例分析，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！
ceph的隔离级别默认都是host级别，也就是说两个副本不会同时落在同一个host 上的磁盘中。这样就保证了有一台机器故障不导致数据不可用。但是如果同时两台机器故障你呢？这就有可能数据丢失造成严重后果。甚至说遇到一个机架突然掉电那这个ceph机器都不可用。解决办法就是提高隔离级别为机架、甚至为了避免重大自然灾害导致一个机房损坏是的数据丢失隔离级别可以提高到机房级别，甚至更高。
下面我们的例子就是隔离级别提高到机架级别。
计算
安全
数据库
网络和加速
企业服务
[root@ceph-node1 opt]# cat decrushmap
# 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 chooseleaf_vary_r 1
tunable chooseleaf_stable 1
tunable straw_calc_version 1
tunable allowed_bucket_algs 54
# devices
device 0 osd.0 class hdd
device 1 osd.1 class ssd
device 2 osd.2 class hdd
device 3 osd.3 class ssd
device 4 osd.4 class hdd
device 5 osd.5 class ssd
device 6 osd.6 class hdd
device 7 osd.7 class hdd
device 8 osd.8 class hdd
device 9 osd.9 class hdd
device 10 osd.10 class hdd
device 11 osd.11 class hdd
# 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 ceph-node1 {
id -3 # do not change unnecessarily
id -4 class hdd # do not change unnecessarily
id -15 class ssd # do not change unnecessarily
# weight 0.058
alg straw2
hash 0 # rjenkins1
item osd.0 weight 0.029
item osd.1 weight 0.029
}
host ceph-node2 {
id -5 # do not change unnecessarily
id -6 class hdd # do not change unnecessarily
id -16 class ssd # do not change unnecessarily
# weight 0.058
alg straw2
hash 0 # rjenkins1
item osd.2 weight 0.029
item osd.3 weight 0.029
}
host ceph-node3 {
id -7 # do not change unnecessarily
id -8 class hdd # do not change unnecessarily
id -17 class ssd # do not change unnecessarily
# weight 0.058
alg straw2
hash 0 # rjenkins1
item osd.4 weight 0.029
item osd.5 weight 0.029
}
host ceph-node4 {
id -9 # do not change unnecessarily
id -10 class hdd # do not change unnecessarily
id -18 class ssd # do not change unnecessarily
# weight 0.058
alg straw2
hash 0 # rjenkins1
item osd.6 weight 0.029
item osd.7 weight 0.029
}
host ceph-node5 {
id -11 # do not change unnecessarily
id -12 class hdd # do not change unnecessarily
id -19 class ssd # do not change unnecessarily
# weight 0.058
alg straw2
hash 0 # rjenkins1
item osd.8 weight 0.029
item osd.9 weight 0.029
}
host ceph-node6 {
id -13 # do not change unnecessarily
id -14 class hdd # do not change unnecessarily
id -20 class ssd # do not change unnecessarily
# weight 0.058
alg straw2
hash 0 # rjenkins1
item osd.10 weight 0.029
item osd.11 weight 0.029
}
# rack
rack rack01 {
id -101 # do not change unnecessarily
id -102 class hdd # do not change unnecessarily
id -103 class ssd # do not change unnecessarily
# weight 0.058
alg straw2
hash 0 # rjenkins1
item ceph-node1 weight 0.058
item ceph-node2 weight 0.058
}
rack rack02 {
id -104 # do not change unnecessarily
id -105 class hdd # do not change unnecessarily
id -106 class ssd # do not change unnecessarily
# weight 0.058
alg straw2
hash 0 # rjenkins1
item ceph-node3 weight 0.058
item ceph-node4 weight 0.058
}
rack rack03 {
id -107 # do not change unnecessarily
id -108 class hdd # do not change unnecessarily
id -109 class ssd # do not change unnecessarily
# weight 0.058
alg straw2
hash 0 # rjenkins1
item ceph-node5 weight 0.058
item ceph-node6 weight 0.058
}
root default {
id -110 # do not change unnecessarily
id -111 class hdd # do not change unnecessarily
id -112 class ssd # do not change unnecessarily
# weight 0.354
alg straw2
hash 0 # rjenkins1
item rack01 weight 0.118
item rack02 weight 0.118
item rack03 weight 0.118
}
# rules
rule replicated_rule {
id 0
type replicated
min_size 1
max_size 10
step take default class hdd
step chooseleaf firstn 0 type rack
step emit
}
rule replicated_ssd {
id 1
type replicated
min_size 1
max_size 10
step take default class ssd
step chooseleaf firstn 0 type rack
step emit
}
[root@ceph-node1 opt]# ceph osd tree
ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
-110 0.35399 root default
-101 0.11800 rack rack01
-3 0.05800 host ceph-node1
0 hdd 0.02899 osd.0 up 1.00000 1.00000
1 ssd 0.02899 osd.1 up 1.00000 1.00000
-5 0.05800 host ceph-node2
2 hdd 0.02899 osd.2 up 1.00000 1.00000
3 ssd 0.02899 osd.3 up 1.00000 1.00000
-104 0.11800 rack rack02
-7 0.05800 host ceph-node3
4 hdd 0.02899 osd.4 up 1.00000 1.00000
5 ssd 0.02899 osd.5 up 1.00000 1.00000
-9 0.05800 host ceph-node4
6 hdd 0.02899 osd.6 up 1.00000 1.00000
7 hdd 0.02899 osd.7 up 1.00000 1.00000
-107 0.11800 rack rack03
-11 0.05800 host ceph-node5
8 hdd 0.02899 osd.8 up 1.00000 1.00000
9 hdd 0.02899 osd.9 up 1.00000 1.00000
-13 0.05800 host ceph-node6
10 hdd 0.02899 osd.10 up 1.00000 1.00000
11 hdd 0.02899 osd.11 up 1.00000 1.00000测试发现达到效果
[root@ceph-node1 opt]# ceph osd map stat rbd_data.10ab6b8b4567.0000000000000042
osdmap e73 pool 'stat' (1) object 'rbd_data.10ab6b8b4567.0000000000000042' -> pg 1.fa3e81bf (1.3f) -> up ([11,2,4], p11) acting ([11,2,4], p11)
# pg的3个副本分别放在了不同rack上以上是“ceph隔离级别的示例分析”这篇文章的所有内容，感谢各位的阅读！希望分享的内容对大家有帮助，更多相关知识，欢迎关注亿速云行业资讯频道！
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原文链接：https://my.oschina.net/wangzilong/blog/4870478
