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+ | ====== Memory intensive Jobs ====== | ||
+ | Jobs requiring more than 2 GB per process have several alternatives. They might use | ||
+ | - a node with more memory, | ||
+ | - a parallel environment with fewer processes | ||
+ | - increased virtual memory, or | ||
+ | - swap space (still experimental). | ||
+ | |||
+ | ==== ad 1. node with more memory ==== | ||
+ | |||
+ | The free space on the nodes of a job can be listed, e.g. by | ||
+ | qstat -F mem_free|grep -B 2 < | ||
+ | | ||
+ | == 256 GB per node == | ||
+ | |||
+ | there are 2 nodes with 64 cores and 256 GB of memory each which are accessible via the '' | ||
+ | < | ||
+ | #$ -q highmem.q | ||
+ | </ | ||
+ | | ||
+ | == 64 GB and 128 GB per node == | ||
+ | |||
+ | several nodes on the VSC-2 have 64 GB or more instead of the 32 GB of the standard nodes. | ||
+ | To use one of these nodes, just add ''' | ||
+ | |||
+ | See also [[doku: | ||
+ | |||
+ | ==== ad 2. parallel environment with fewer processes | ||
+ | |||
+ | | ||
+ | |||
+ | |||
+ | ==== ad 3. increased virtual memory ==== | ||
+ | |||
+ | Some programs allocate more memory than they use. This was especially true in old FORTRAN 77 programs, which had to decide at compile time how much memory will be used. These programs are allowed to allocate 50% more memory than available by ''# | ||
+ | |||
+ | ==== ad 4. swap space (still experimental) ==== | ||
+ | |||
+ | A novel feature of the VSC-2 is remote swap space (implemented using 'SCSI RDMA Protocol', |