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

[Patrick Shopbell]

Hi all -
As the original poster of this thread, I should probably just
weigh in that it is indeed possible that something was out of
order when I brought up our setup with the new MGS+MDS. I
*thought* I did it right, since I was following the
instructions in section 14.5 of the manual (Changing a Server
NID), and that section does indeed advise the proper initial
order:

MGS, MDS, OST, Clients

But maybe I got a client or something in there too early. I
also had some issues with the NIDs of the OSTs pointing to
an old ethernet interface first, so maybe that confused
things.

The solution was perfect, though. Thanks to Colin and this list.
--
Patrick



On 3/7/13 8:53 AM, Colin Faber wrote:
> 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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>>
>
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-- 
*--------------------------------------------------------------------*
| Patrick Shopbell               Department of Astronomy             |
| pls at astro.caltech.edu          Mail Code 249-17                    |
| (626) 395-4097                 California Institute of Technology  |
| (626) 568-9352  (FAX)          Pasadena, CA  91125                 |
| WWW: http://www.astro.caltech.edu/~pls/                            |
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