HP XC System 2.x Software - Manual (Page 20)

different roles that can be assigned to a client node, the following roles contain services that are
of special interest to the general user:
login role The role most visible to users is on nodes that have the login role.
Nodes with the login role are where you log in and interact with the
system to perform various tasks. For example, once logged in to a
node with login role, you can execute commands, build applications,
or submit jobs to compute nodes for execution. There can be one or
several nodes with the login role in an HP XC system, depending
upon cluster size and requirements. Nodes with the login role are
a part of the Linux Virtual Server ring, which distributes login
requests from users. A node with the login role is referred to as
a login node in this manual.
compute role The compute role is assigned to nodes where jobs are to be
distributed and run. Although all nodes in the HP XC system are
capable of carrying out computations, the nodes with the compute
role are the primary nodes used to run jobs. Nodes with the compute
role become a part of the resource pool used by LSF-HPC and
SLURM, which manage and distribute the job workload. Jobs that
are submitted to compute nodes must be launched from nodes
with the login role. Nodes with the compute role are referred to as
compute nodes in this manual.
1.1.3 Storage and I/O
The HP XC system supports both shared (global) and private (local) disks and file systems.
Shared file systems can be mounted on all the other nodes by means of Lustre or NFS. This
gives users a single view of all the shared data on disks attached to the HP XC system.
SAN Storage
HP XC uses the HP StorageWorks Scalable File Share (HP StorageWorks SFS), which is based
on Lustre technology and uses the Lustre File System from Cluster File Systems, Inc. This is a
turnkey Lustre system that is delivered and supported by HP. It supplies access to Lustre file
systems through Lustre client-server protocols over various system interconnects. The HP XC
system is a client to the HP StorageWorks SFS server.
Local Storage
Local storage for each node holds the operating system, a copy of the HP XC system software,
and temporary space that can be used by jobs running on the node.
HP XC file systems are described in detail in Section 1.1.4.
1.1.4 File System
Each node of the HP XC system has its own local copy of all the HP XC System Software files
including the Linux distribution and also has its own local user files. Every node may also import
files from NFS or Lustre file servers. HP XC System Software supports NFS 3 including both
client and server functionality. HP XC System Software also enables Lustre client services for
high-performance and high-availability file I/O. These Lustre client services require the separate
installation of Lustre software, provided with the HP Storage Works Scalable File Share (SFS).
In the case of NFS files, these can be shared purely between the nodes of the HP XC System,
or alternatively can be shared between the HP XC and external systems. External NFS files
can be shared with any node having a direct external network connection. It is also possible to
set up NFS to import external files to HP XC nodes without external network connections, by
routing through a node with an external network connection. Your system administrator can
1-2 Overview of the User Environment