[Gluster-devel] distributed locking

[Brian Taber]

I completed the tests:


TEST : TRY TO WRITE ON A READ 
LOCK:.====================================================================================================
TEST : TRY TO WRITE ON A WRITE
LOCK:====================================================================================================
TEST : TRY TO READ  ON A READ 
LOCK:====================================================================================================
TEST : TRY TO READ  ON A WRITE
LOCK:====================================================================================================
TEST : TRY TO SET A READ  LOCK ON A READ 
LOCK:====================================================================================================
TEST : TRY TO SET A WRITE LOCK ON A WRITE
LOCK:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
TEST : TRY TO SET A WRITE LOCK ON A READ 
LOCK:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
TEST : TRY TO SET A READ  LOCK ON A WRITE
LOCK:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
TEST : TRY TO READ LOCK THE WHOLE FILE BYTE BY
BYTE:====================================================================================================
TEST : TRY TO WRITE LOCK THE WHOLE FILE BYTE BY
BYTE:====================================================================================================

process number : 100 - Remote clients: 2 local client 1 - Total client 3 -
Total concurent tests: 300
process number running test successfully :
300 process of 300 successfully ran test : WRITE ON A READ  LOCK
300 process of 300 successfully ran test : WRITE ON A WRITE LOCK
300 process of 300 successfully ran test : READ  ON A READ  LOCK
300 process of 300 successfully ran test : READ  ON A WRITE LOCK
300 process of 300 successfully ran test : SET A READ  LOCK ON A READ  LOCK
100 process of 300 successfully ran test : SET A WRITE LOCK ON A WRITE LOCK
100 process of 300 successfully ran test : SET A WRITE LOCK ON A READ  LOCK
100 process of 300 successfully ran test : SET A READ  LOCK ON A WRITE LOCK
100 process of 300 successfully ran test : READ LOCK THE WHOLE FILE BYTE
BY BYTE
100 process of 300 successfully ran test : WRITE LOCK THE WHOLE FILE BYTE
BY BYTE


Looks like there is a couple of issues there...



> Brian Taber wrote:
>> I just ran lock tests I found in the QA section on 2 servers at the same
>> time with 500 threads each, they all ran successfully.  I am currently
>> running the TLA version of gluster, I don't know if that makes a
>> difference...
>
> So do I. Could you try the test in network mode? The source available
> from the link on the GlusterFS QA page doesn't support network-based
> tests (however, it does by documentation). There's an updated version at
>
> http://nfsv4.bullopensource.org/tools/tests/page45.php
>
> that can really do the trick.
>
> After compiling, you run
>
> locktests -f <file> \
>           -n <number of processes per node> \
>           -c <number of nodes - 1>
>
> on one server and
>
> locktests --server <servernode>
>
> on the other(s). This will test locking the same file from two clients.
>
> I would be interested in your results and your configuration, if you can
> make them public.
>
> Thanks,
> --
> cc
>
>>> Brian Taber wrote:
>>>> I have been running Dovecot and Postfix with a 2 brick setup and posix
>>>> locking enabled on each brick for a while with no problems.  This is a
>>>> Maildir setup...  Dovecot is setup to use fcntl for locking....
>>>> remember
>>>> that gluster does not support flock as fuse does not support it...
>>> Yes, I'm aware of this. But in your place, I would stop doing this
>>> until
>>> the GlusterFS QA test runs successfully. If it doesn't, then not losing
>>> data with such a setup is just a matter of luck. And for this storage
>>> application, I can't accept the risk.
>>>
>>>>> On Fri, 30 Nov 2007, Székelyi Szabolcs wrote:
>>>>>
>>>>>> Everything works fine as long as I don't introduce locking, which is
>>>>>> essential if one wishes to use the storage eg. as a backend for a
>>>>>> mail
>>>>>> server.
>>>>> I'm sorry that I cannot answer your question, but do you have a
>>>>> choice
>>>>> in
>>>>> what mail server to use? Those that use the Maildir format (Like for
>>>>> example Postfix together with Courier-IMAP) does not need locking.
>
>
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