[Mauiusers] Nodeset behavior

Hemanth Yamijala yhemanth at yahoo-inc.com
Thu Feb 7 09:41:19 MST 2008


Hi,

We have a need to distribute our Torque jobs across nodes which are in
different racks within our clusters. We tried doing this as follows:

1. Logically split the entire set of nodes into groups, giving each
group a name.
2. Assigned the group name as a 'node property' for each node in Torque.
So, the logical grouping was something like this:

group1 = { n1, n2, n3, n4 }
group2 = { n5, n6, n7, n8 }
group3 = { n9, n10}

3. Configured Maui as follows:

NODESETATTRIBUTE FEATURE
NODESETPOLICY     ONEOF
NODESETLIST group1 group2 group3

4. We tested this setup by submitting jobs of varying sizes.

What we found was the following:

- echo "sleep 30" | qsub -l nodes=4

allocated nodes within a group, as long as they were available

# to test spill over.
- echo "sleep 30" | qsub -l nodes=6 

allocated nodes pretty much randomly, even when all nodes are free.

What we want is in the second case, Maui should allocate nodes first
within a group, and then within a second group (as much as possible),
and so on. For e.g. the 6 nodes could be spread across group1 (4 nodes)
and group3 (2 nodes), or even group1 (4 nodes) and group2 (2 nodes).

Instead what is happening is that the allocation seems to be somewhat
random. Something like 2 nodes from each group.

Is this expected ? Can we configure Maui to behave in the manner
described ?

Thanks
Hemanth


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