Thanks for your help!^^
I am very appreciate.
2011/4/28 Sage Weil <sage@xxxxxxxxxxxx>:
> On Wed, 27 Apr 2011, doki74216@xxxxxxxxx wrote:
>> Dear developers
>>
>> I am testing the reliability of MDS in Ceph File System.
>> As we know, the default setting, there are one active MDS and one standby MDS.
>> I want to test the reliability of MDS.
>> Here is my testing scenario:
>> As easy to understand, here I assume the active MDS as mds0 and the
>> standby one is mds1.
>> I write data and stop the mds0 daemon by "ceph mds stop 0" at the same time.
>> Will the standby mds1 change its status to active?
>> I think the system should be normal and the data should not loss even
>> though there is just one MDS.
>> But there are many problem I met....><
>>
>> (1) I want to know which mds is active and standby.
>> But there are different answer when I type different commands.
>>
>> 1. When I type "ceph mds stat".
>> It shows: (0=up: active), 1 up: standby
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Does it means mds0
>
> Right, the 0 means mds0.
>
>> is active and mds1 is standby ?
>> 2.When I type "ceph mds dump -o -"
>> It shows: mds0 is standby and mds1 is active.
>>
>> My question is: Why there are different status about mds0 and mds1?
>> Which one is correct?
>
> It sounds like you named the MDS's with numeric identifiers. You should
> use non-numeric names to avoid this confusion, like mds.a and mds.b. The
> numeric role/rank (mds0, mds1) is assigned to cmds instances dynamically
> based on who is up and needed in which role at the time.
>
>> (2) I want to know the issue about stoping the active mds.
>> If the command which "ceph mds stat" can show the active mds correctly,
>> the active mds must be mds0 and the other mds1 is standby.
>> So I type"ceph mds stop 0".
>> It shows: ?telling mds0 192.168.200.185:6800/14819 to stop?(0)
>> ^^^^^^^^^^^^^^^^^^ mds1's IP.
>> 1. Why it shows the system stoping mds0 but mds1's IP ?
>
> The 'stop' command takes the dynamic role, not the name.
>
> Hope this clears it up!
> sage
>
>
>>
>> 2. When I type "ceph -w", here is the log:
>> ======================================
>> mds e43: 1/1/1 up {0=up:active}, 1 up standby
>> mds e44: 1/1/1 up {0=up:stoping}, 1 up standby
>> mds e45: 1/1/1 up {0=up:replay}
>> mds e46: 1/1/1 up {0=up:reconnect}
>> mds e47: 1/1/1 up {0=up:rejoin}
>> mds e44: 1/1/1 up {0=up:active}
>> =====================================
>> >From the log, which MDS does the system stop?
>> My command which is"ceph mds stop 0", but the log should not be {1=up:active}?
>> It really confuse me...
>>
>> 3. When I type"ceph mds dump ?o ?", here is the log:
>> 4920: 192.168.200.184:6800/30000 ?0? mds0.12 up:active seq 40828
>> ^^^^^^^^^^^^^^^^^^^ mds0's IP
>> Why does the system leave the mds0?
>>
>> Please help me solving these problem, I am very confused...
>> Thanks a lot~~~^^
>>
>>
>> By the way, this is my testing environment :
>> ==================================================================================
>> I set 7 servers which include 3 MONs(host1 host2 host3), 2 MDSs(host4
>> host5) and 2 OSDes(host6 host7).
>> The version ceph 0.26 is in my system.
>> ==================================================================================
>> --
>> Best Regards,
>> Stefanie Chen
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>
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