[elephant-devel] using one store with mutiple lisp instances

[Ian Eslick]

I should clarify the first sentence.  With a bunch of external machinery to support a distributed transaction model, it's possible to run BDB across machines, but Elephant doesn't have any of it so can only use the built-in shared memory locking facility.  There was some talk a year or two ago about doing a distributed locking solution for Elephant, but I don't know the status of it.

Thanks,
Ian

On May 4, 2011, at 11:51 AM, Ian Eslick wrote:

> BDB does not work across multiple machines, its transaction support relies on a shared memory region to handle locking so any shared memory architecture (with multiple CPUs) works fine but separate machines and a NAS device don't work.  You'll have to use the Postgres store (5x slower, but reasonably scalable) if you want concurrent access to a single Elephant DB from multiple machines.
> 
> On May 4, 2011, at 11:37 AM, Lukas Georgieff wrote:
> 
>> Hi Leslie,
>> 
>>> Hi Lukas,
>>> 
>>>> Has someone any experience using elephant in that manner?
>>> 
>>> Yes -- lots in fact. But you need to ask a specific question.
>> 
>> well, if the points I've mentioned before are correct, I've only one
>> specific question :-)
>> 
>> We want to share a network device that contains the Berkeley-DB files.
>> This BDB shall be accessed by two or more other machines that execute a SBCL
>> interpreter with our program.
>> 
>> I am not sure if this works similar to executing two SBCL instances on one
>> machine, because I don't know if the elephant-bdb-locking works
>> Across several machines!
>> 
>> 
>> Thanks in advance,
>> 
>> Lukas
>> 
>> 
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> 
> 
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