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Dell HPC NFS Storage Solution High Availability Configurations with Large Capacities
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4.2. Storage configuration
In previous versions of the solution, the file system had a maximum of four virtual disks. A Linux
physical volume was created on each virtual disk. The physical volumes were grouped together into a
Linux volume group and a Linux logical volume was created on the volume group. The XFS file system
was created on this logical volume.
Storage and file system layout Figure 6.
With this release, if the configuration includes more than four virtual disks, the Linux logical volume
(LV) is extended, in groups of four, to include the additional PVs. In other words, groups of four virtual
disks are concatenated together to create the file system. Data is striped across each set of four virtual
disks. However it is possible to create users and directories such that different data streams go to
different parts of the array and thus ensure that the entire storage array is utilized at the same time.
The configuration is shown in Figure 6 for a 144TB configuration and a 288TB configuration.
Additionally, with this release the SAS cabling uses the asymmetric ring cabling scheme as shown in
black lines in the figure. The previous cascade cabling scheme can also be used instead.
4.3. Red Hat Enterprise Linux operating system
In previous versions of NSS-HA, RHEL 5.5 is deployed. In the current version, RHEL 6.1 is used.
Compared to RHEL 5.5, a significant change within RHEL 6.1 is the HA cluster suite. The updated HA
cluster suite includes the following major changes
(3)
:
 The cluster configuration GUI, Conga, is updated and has a new interface
 A restart-disable failure for a service is added for configuring HA service
 An independent sub tree as non-critical can be configured
Instructions to configure the HA cluster with RHEL 6.1 are listed in Appendix A: NSS-HA Recipe in this
document. Since there are several significant changes in how the HA functionality is managed with this