[Linux-cluster] When using GFS+DLM, will DLM manage the locks on journals?

Gordan Bobic gordan at bobich.net
Wed May 14 22:32:21 UTC 2008

Ja S wrote:
> --- Gordan Bobic <gordan at bobich.net> wrote:
>> Ja S wrote:
>>> Hi, All:
>>> Just want to get a clarification.
>>> When using GFS+DLM, will the locks of journals be
>>> managed also by DLM in the same way as that for
>> normal
>>> data files?
>> My understanding is that there is no locking on the
>> journals across 
>> nodes except when a node gets fenced and it's
>> journal needs to be 
>> replayed to ensure data is consistent. Each node has
>> it's own journal.
> Thanks. Then what this "can't acquire the journal
> glock:" error is about?

I think the journals are allocated on a first-come first-served basis to 
the nodes as they connect to the shared storage. Each node locks it's 
own journal to ensure that it is marked as "in use". That's why you'll 
see that message at mount time. But I don't think there is any journal 
locking going on under normal operation.


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