1. Improving ARC backends: Condor and SGE/GE LRMS interface
Adrian Taga
University of Oslo

2. LRMS bakends in ARC supported: PBS&variants, LSF, Condor, SGE, LL
perl/sh wrappers around the command line interface of LRMS
advantage: easy to modify
No clear structure
Scripts for:
Populating InfoSystem
Job control (submit, get status, kill)
Automated system like atlas production needs to clearly distinguish failures of the job from failures related to LRMS. In special, failures due to exceeded resource limits.

3. Queues in Condor Why have queues? Inhomogeneous clusters
Problem: Condor has no notion of queues
Solution: use ClassAd mechanism to partition the cluster.
Example:
Queues defined based on memory size
So far, Condor backend did not support queues.
Why d we need queues? -
Condor pools tend to be quite heterogeneous.
The way heterogenity is handled innordugrid is by dividing the cluster into separate queues of more or less
identical machines. However, condor does not have the notion of queues like
other batch systems have. Still, it's possible to divide up the condor pool in
virtual 'queues' by expploiting the flexible classAd mechanism.
[queue/large]
requirements="(Opsys == "linux" && Arch == "intel""
requirements=" && (Disk > && Memory > 2000)"
[queue/small]
requirements="(Opsys == "linux" && Arch == "intel”"
requirements=" && (Disk > && Memory <= 2000 && Memory > 1000)"

4. Error reporting Many LRMS backends
Inconsistent reporting of LRMS errors
Clear diagnosis is needed for ATLAS prodsys
Scenario: job exceeded resource limits
PBS & Co – natively reports
WallTime, CpuTime, Memory limit exceeded
Exitcode < 256 from job,
Exitcode ≥ 256 resource limit hit
Condor, SGE - provide no clear diagnosis, workarounds needed
Automated system like atlas production needs to clearly distinguish failures of the job from failures related to LRMS. In special, failures due to exceeded resource limits.

5. Thank you