HP XC System Software User's Guide Version 3.2

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.
1.1.5 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
The HP XC system 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 from 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 “File System”.
1.1.6 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; it also has its own local user files. Every node can also import
files from NFS or Lustre file servers. HP XC System Software uses 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).
NFS files can be shared exclusively among the nodes of the HP XC System or 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 choose to use either the HP XC administrative
network or the HP XC system interconnect for NFS operations. The HP XC system interconnect
can potentially offer higher performance, but only at the potential decrease in the performance
of application communications.
For high-performance or high-availability file I/O, the Lustre file system is available on HP XC.
The Lustre file system uses POSIX-compliant syntax and semantics. The HP XC System Software
includes kernel modifications required for Lustre client services which enables the operation of
the separately installable Lustre client software. The Lustre file server product used on HP XC
is the HP StorageWorks Scalable File Share (SFS), which fully supports the HP XC System
Software.
The SFS also includes HP XC Lustre client software. The SFS can be integrated with the HP XC
so that Lustre I/O is performed over the same high-speed system interconnect fabric used by
1.1 System Architecture 25