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How do I find LSF documentation?
The vendor website has documentation, the cluster man pages and this local link.
How to request memory resources on the cluster?
Memory usage is often hard to estimate in a new context or program. Generally speaking the larger the input data the more memory and perhaps other resources are used. Since the cluster has compute nodes with different amounts of memory, we have created an LSF resource so that you may request in a bsub job submission the upper limit of memory required. This is helpful in many ways in preventing resource collisions and to other jobs sharing the same compute node.
The LSF defined resources are: Mem8, Mem16, Mem24, Mem32, Mem48, Mem64, and Mem80. These correspond to gigabytes of ram.
What happens if I don't explicitly use a defined ram memory resource when I submit a job?
LSF will place your job(s) on a node(s) that is considered available without understanding your needs for ram. If your job starts to request more ram than is available on that node given it's current load, then your job(s) may be at risk for taking too long to run or may put the node in an unresponsive state. This can affect other users jobs.
Suppose my jobs have a very small memory requirement, say 100meg, do I have to use the defined memory resources?
Not usually. There are many cases like this, and experience tells us that this is usually not a problem.
My program needs access to more than 16 gig or ram, what are my options?
An lsf LSF resource has been defined to identify those nodes with 32 24 gig of ram. You access this through a bsub command line option, -R, when you submit your job.
-bash-3.2$ bsub -R bigmem Mem24 -queue normal_public ./myprogram
I see that there are some nodes with more than 32gig ram, such as 48 and 96 gig. How do I access them in exclusive mode since I need almost all the ram ?-bash-3.2$ bsub -q express_public -x -R "mem > 40000" ./myprogram
orand my expected job duration is just minutes?
-bash-3.2$ bsub -q exbatchexpress_public -x -R "mem > 40000" Mem48 ./myprogram
I have a program that is threaded. Is it possible to submit a job that will "take over" a node, or at least the 4 cores on a single chip?
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How does one actually invoke a job exclusively?
LSF bsub command has the -x option. To send your job to a node that has extra memory and runs exclusively :for hours.
-bash_-3.2$ bsub -x -q expressexbatch_public -x -R bigmem Mem16 .../myprogram
How does one make use of nodes with /scratch2 storage?
Note that is is disk storage and not ram memory.
Access to this storage is by request. Please make this request via cluster-support@tufts.edu.
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