[Lustre-discuss] lustre startup sequence Re: OSTs not activating following MGS/MDS move

[Colin Faber]

I should make this clear,

This is only critical for initial start up. Successive startups don't 
matter so much as services have already been registered.

-cf

On 03/07/2013 09:52 AM, DEGREMONT Aurelien wrote:
> Hello
>
> AFAIK there is 2 orders:
>  - If you are started your filesystem for the first time (or using 
> --writeconf), order is :
> MGS, MDS, OST, Clients
>  - On normal start
> MGS, OST, MDS, Clients
>
> There is a patch on some recent Lustre release to be able to use the 
> first order any time but I would advise to use the second one anyway 
> as it avoids starting MDS first, lacking connection to OST, and then 
> reconnecting to them when they are really started.
>
>
> Aurélien
>
>
> Le 07/03/2013 17:48, Colin Faber a écrit :
>> Hi Yes,
>>
>> Thanks for finding this Alex. The manual should be updated with the
>> correct order.
>>
>> -cf
>>
>>
>>
>> On 03/07/2013 09:39 AM, Alex Kulyavtsev wrote:
>>> Hi Colin.
>>> This is not what the manual says.
>>>
>>> Shall it be corrected then? Or, add description for startup sequence
>>> in different situations (first start, restart).
>>>
>>> The manual (or online information) does not describe graceful shutdown
>>> sequence for separate MGS/MDT configuration, it will be nice to add
>>> that too.
>>>
>>> Alex.
>>>
>>> E.g.
>>> http://wiki.lustre.org/manual/LustreManual20_HTML/LustreOperations.html#50438194_24122 
>>>
>>> and similar
>>> http://build.whamcloud.com/job/lustre-manual/lastSuccessfulBuild/artifact/lustre_manual.xhtml#dbdoclet.50438194_24122 
>>>
>>>>
>>>>      13.2 Starting Lustre
>>>>
>>>> The startup order of Lustre components depends on whether you have a
>>>> combined MGS/MDT or these components are separate.
>>>>
>>>>    * If you have a combined MGS/MDT, the recommended startup order is
>>>>      OSTs, then the MGS/MDT, and then clients.
>>>>
>>>>    * If the MGS and MDT are separate, the recommended startup order
>>>>      is: *MGS, then OSTs, then the MDT, and then clients.*
>>>>
>>>
>>>
>>> On Mar 7, 2013, at 9:51 AM, Colin Faber wrote:
>>>
>>>> Hi Christopher,
>>>>
>>>> In general this can happen when your initial remount of the various
>>>> services is in thewrong order.
>>>>
>>>> Such as MGS -> OST -> MDT -> Client. or MGS -> MDT -> Clients -> OST,
>>>> etc.
>>>>
>>>> During initial mount and registration it's critical that your mount be
>>>> in the correct order:
>>>>
>>>> MGS -> MDT -> OST(s) -> Client(s)
>>>>
>>>> CATALOG corruption, or out of order sequence is more rare on active 
>>>> file
>>>> system, but is possible. The simple fix here as described below is to
>>>> just truncate it and all should be well again.
>>>>
>>>> -cf
>>>>
>>>> ailing list
>>>> Lustre-discuss at lists.lustre.org 
>>>> <mailto:Lustre-discuss at lists.lustre.org>
>>>> http://lists.lustre.org/mailman/listinfo/lustre-discuss
>>>
>>>
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