How to configure the hdparm test module for diskless, multi-drive, or external storage nodes

The primary use of the Intel® Cluster Checker hdparm test module is to evaluate the primary disk drive on each node. By design, it’s only capable of testing performance on a single disk drive per node.

Configuration of this test module is dependent on the type of storage devices used for each node. Many clusters will implement multiple storage devices; for example, all nodes may include a local hard drive and also access shared, external storage. In this case, hdparm should be configured to test the local drive.  Other cases and their configurations are described below.

Diskless clusters


This test module can be excluded for diskless clusters. If the head node contains a disk drive, Intel® Cluster Checker can be configured to evaluate just that device. For example:

<hdparm>
  <check_compute>0</check_compute>
</hdparm>

Multi-drive nodes


hdparm is capable of evaluating a single drive. For nodes with multiple hard drives, it’s beneficial to evaluate the disk drive with the most activity or impact on application performance. This is most likely the hard drive containing the /tmp directory or partition, or the drive used for application scratch space.  For example, if the primary application scratch space is located on the device /dev/sdb:

<hdparm>
  <device>/dev/sdb</device>
</hdparm>

External storage system



If shared, external storage is the only storage medium used for nodes, the module should be excluded. The hdparm test module is not capable of evaluating devices that do not support kernel-level ioctl() operations. If the external storage system appears to the Linux kernel as an ATA, SATA, or SCSI local storage device, hdparm may support it.

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