Ceph集群提示insufficient standby MDS daemons available

ceph集群健康检查出现问题，提示insufficient standby MDS daemons available

具体信息如下

[root@ceph-01 ~]# ceph -s
  cluster:
    id:     c8ae7537-8693-40df-8943-733f82049642
    health: HEALTH_WARN
            insufficient standby MDS daemons available

  services:
    mon: 3 daemons, quorum ceph-01,ceph-02,ceph-03 (age 45h)
    mgr: ceph-03(active, since 46h), standbys: ceph-02, ceph-01
    mds: cephfs-abcdocker:1 cephfs:1 i4tfs:1 {cephfs-abcdocker:0=ceph-03=up:active,cephfs:0=ceph-02=up:active,i4tfs:0=ceph-01=up:active}
    osd: 4 osds: 4 up (since 46h), 4 in (since 8w)
    rgw: 2 daemons active (ceph-01, ceph-02)

  task status:

  data:
    pools:   19 pools, 880 pgs
    objects: 8.85k objects, 31 GiB
    usage:   97 GiB used, 83 GiB / 180 GiB avail
    pgs:     880 active+clean

  io:
    client:   2.0 KiB/s wr, 0 op/s rd, 0 op/s wr

此时集群已经提示警告，状态已经不是OK

排查思路:

检查 ceph 健康状况

[root@ceph-01 ~]# ceph health detail

HEALTH_WARN insufficient standby MDS daemons available
MDS_INSUFFICIENT_STANDBY insufficient standby MDS daemons available
    have 0; want 1 more

一或多个文件系统配置的是需要一定数量的灾备守护进程（包括灾备重放 standby-replay 守护进程），但是集群内却没有足够多的守护进程。非重放的灾备进程可算进任意文件系统（即它们可重叠）。这个警告可用 ceph fs set standby_count_wanted 来配置， count 配置为 0 时禁用此功能。

可以将所有的cephfs fs_name修改为0

[root@ceph-01 ~]# ceph -s
  cluster:
    id:     c8ae7537-8693-40df-8943-733f82049642
    health: HEALTH_OK

  services:
    mon: 3 daemons, quorum ceph-01,ceph-02,ceph-03 (age 46h)
    mgr: ceph-03(active, since 46h), standbys: ceph-02, ceph-01
    mds: cephfs-abcdocker:1 cephfs:1 i4tfs:1 {cephfs-abcdocker:0=ceph-03=up:active,cephfs:0=ceph-02=up:active,i4tfs:0=ceph-01=up:active}   #mds:1就是我们需要禁用的fs_name
    osd: 4 osds: 4 up (since 46h), 4 in (since 8w)
    rgw: 2 daemons active (ceph-01, ceph-02)

  task status:

  data:
    pools:   19 pools, 880 pgs
    objects: 8.80k objects, 31 GiB
    usage:   97 GiB used, 83 GiB / 180 GiB avail
    pgs:     880 active+clean

  io:
    client:   54 KiB/s rd, 3.0 KiB/s wr, 54 op/s rd, 36 op/s wr

具体操作如下

[root@ceph-01 ~]# ceph fs set cephfs-abcdocker  standby_count_wanted 0
[root@ceph-01 ~]# ceph fs set cephfs  standby_count_wanted 0
[root@ceph-01 ~]#  ceph fs set i4tfs  standby_count_wanted 0

还有一种方法，增加mds双主
https://www.jianshu.com/p/0ef905f039d6