Serveral installations of OAR are known to have reached more than several millions of jobs. With the corresponding size of the OAR database, some problems may arise, first of all depending on the sizing of the database server in use.
The main CIMENT cluster for instance (froggy) currently runs jobs with id > 11.000.000, with not known issues. CIMENT uses a PostreSQL database with a dedicated server (not a VM) with the follwing hardware specs:
However, some other installations (probably with a less powerful server) are known to have required some maintenance in order to keep OAR fully responsive.
Therefore, this page gathers some know-how when it comes to shrink a OAR database which is becoming too big.
The solution here is to create a fresh new database for OAR, keeping just the structure of the OAR installation (first of all the definition of the resources), but no job data.
As a result, the counter of job ids will reset to 1.
This solution is fairly easy, but with the drawback of breaking history (e.g. job dependency if any), and forcing to stop running jobs and emptying queues (i.e. breaking the continuity of service).
It involves the following steps:
Please feel free to contribute to this page by reporting remarks to the oar-users@ mailing list.