Partitions¶
A partition is a logical collections of nodes that comprise different hardware resources and limits to help meet the wide variety of jobs that get scheduled on the cluster. Nodes can belong to more than one partition.
There are several types of partitions:
- General access (e.g. shared, interactive, gpu, transfer)
- Application only (e.g. sas)
- GPU (equipped with GPU cards)
- PI-owned (for use only by members of the PI's group)
Jobs and Partitions¶
Jobs can be submitted to multiple partitions. They will generally start in the first partition that has the required resources. However there are a number of ways in which partitions are configured which may nudge a pending job to one partition over others. Pending jobs in some partitions are evaluated ahead of others. Priorities can be set on some partitions (such as interactive) as described here.
Array jobs seem to be able to dispatch child jobs to any of the partitions specified. We are not 100% sure of this -- they might all be run into the first partition chosen. (If the latter is true, you may not want to tie your array completion to a partition that has many fewer resources than your other option(s).)
PI Partitions¶
JHPCE exists because Primary Investigators worked together to create a cluster. They share their resources via public partitions (see cost recovery descriptions here and here).
Only submit jobs to these partitions if you are a member of the Primary Investigator's research groups or have been given explicit permission to do so. If you are in doubt, ask before submitting. Jobs from non-group members will be killed and repeated abuse will lead to repercussions.
Public Partitions¶
Partitions shared, interactive, gpu, sas and transfer are considered public and available to all.
Specific use
Only jobs which require the use of GPU cards should be submitted to the gpu partition.
Only jobs which require the use of the SAS application should be submitted to the sas partition.
Only jobs related to transferring data into or out of the cluster should be submitted to the transfer partition.
The public partitions provide low-priority access to unused capacity throughout the cluster. Capacity on the shared queue is provided on a strictly “as-available” basis and serves two purposes.
First it provides surge capacity to stakeholders who temporarily need more compute capacity than they own, and second, it gives provides non-stakeholders access to computing capacity.
Scheduling polices attempt to harvest unused capacity as efficiently as possible while mitigating the impact on the rights of stakeholders to use their resources. The JHPCE service center does not guarantee that stakeholders will provide sufficient excess capacity to meet non-stakeholders needs, however in practice the cluster is rarely operating at full capacity so there is usually ample computing capacity on the shared queue.
Getting Info About Partitions¶
Our command slurmpic shows information about partitions, including the member nodes, their current utilization, and some summary statistics.1 By default it displays the shared partition. Specific partitions can be displayed using slurmpic -p partitionname. All of the nodes in all of the GPU partitions can be displayed with slurmpic -g. Run slurmpic -h to see usage notes.
The best way to see the configuration of a partition is with the scontrol command. (Vendor's scontrol manual page. Our local scontrol tips page.)
scontrol show partition partitionname
The command sinfo shows information about all of the partitions. It has many options, so you can also use it to see information about nodes. (Note: Partitions which require group membership to submit to are only visible via sinfo to members of those groups. Because the local command slurmpic uses sinfo to retrieve information, the output of slurmpic -a (show all nodes) will omit those private PI partitions' nodes.)
CPU Partitions¶
Public CPU Partitions¶
The CPU and RAM limits for shared change depending on node availability. We change the QOS shared-defaultup and down to try to keep RAM, in particular, limited to about 20% of the total available in order to assure equitable access to the resources. You can learn more about QOS here.
Limits for CPU cores, RAM and Time (default/maximum)
| Name | Type | Core | RAM | Time | Notes/Use |
|---|---|---|---|---|---|
| shared | public | 100 | 512MB | (1d/90d) | DEFAULT |
| interactive | public | 2 | 20gb | (1d/90d) | Small but accessible |
| gpu | public | (none) | (none) | (1d/90d) | Only for GPU jobs |
| sas | application | (none) | (none) | (none/90d) | Licensed for SAS |
| transfer | public | no | (none) | (none) | (none/90d) |
To reduce table width, column names are terse.
PI CPU Partitions¶
Limits for CPU cores, RAM and Time (default/maximum)
| Name | Type | Core | RAM | Time | Notes/Use |
|---|---|---|---|---|---|
| bader | PI | (none) | (none) | (none/90d) | |
| cancergen | PI | (none) | (none) | (none/90d) | |
| caracol | PI | (none) | (none) | (none/90d) | UNIX group |
| cee | PI | (none) | (none) | (none/90d) | |
| cegs2 | PI | (none) | (none) | (none/90d) | |
| chatterjee | PI | (none) | (none) | (none/90d) | |
| echodac | PI | (none) | (none) | (none/90d) | |
| gwas | PI | (none) | (none) | (none/90d) | not yet defined |
| hl | PI | (none) | (none) | (none/90d) | |
| hpm | PI | (none) | (none) | (none/90d) | not yet defined |
| hongkai | PI | (none) | (none) | (none/90d) | |
| katun | PI | (none) | (none) | (none/90d) | UNIX group |
| mommee | PI | (none) | (none) | (none/90d) | |
| stanley | PI | (none) | (none) | (none/90d) | UNIX group |
| sysadmin | admin | (none) | (none) | (none/90d) | For system testing |
GPU Partitions¶
Limits for CPU cores, RAM and Time (default/maximum)
| Name | Type | Requires Approval | Core | RAM | GPU | Time | Notes/Use |
|---|---|---|---|---|---|---|---|
| gpu | public | no | (none) | (none) | (none) | (1d/90d) | |
| bestgpu | PI | yes | (none) | (none) | (none) | (none/90d) | |
| caracol | PI | yes | (none) | (none) | (none) | (none/90d) | |
| neuron | PI | yes | (none) | (none) | (none) | (none/90d) |
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Note that the statistics displayed are for that partition, not the whole cluster. Also, memory and CPU use of nodes that are DOWN or in DRAIN are not included in the stats. ↩