[Lustre-discuss] Lustre & SQLite

[Michal Wesolowski]

Oleg Drokin wrote:
> Hello!
> 
> On Feb 11, 2009, at 4:19 PM, Michal Wesolowski wrote:
>> In SQLite documentation (http://www.sqlite.org/lockingv3.html) there is
>> statement that this db engine uses advisory locks to protect shared 
>> date. I know
>> Lustre doesn't implement this yet. So my questions are:
>> - Am I right suspecting that for current Lustre version (1.6.6) there 
>> is real
>> risk of SQLite files corruption (in a sense of their integrity - not 
>> from fs
>> point of view) even if using flock option?
>> - Are advisory locks still planned to come with 1.8 version (as it is 
>> indicated
>> in current Lustre Operation Manual, but there is no such feature in 
>> November
>> Roadmap slide on wiki.lustre.org site)?
> 
> Lustre supports posix advisory locks. You can enable it with -o flock 
> mount option
> (on all clients).
> -o localflock is posix advisory locks with no cluster coherency, so it 
> is unsafe
> for the same database used across several nodes.
> 
> Bye,
>     Oleg

Thanks Oleg

My interpretation of Lustre documentation was that flock/localflock implements 
only mandatory locks.
So I assume statement in Lustre Manula (ver. 15, page 16-1):

Note – Advisory fcntl/flock/lockf locks will be available in Lustre 1.8.

is a documentation bug, isn't it?

Thanks

Michal