Manage the System

Important information for system administrators.

Caution is encouraged when executing system management commands and procedures; hasty actions can result in down time and lost data.

Important: Use persistent SCSI device names.

This does not apply to SMW disks: SCSI device names (/dev/sd*) are not guaranteed to be numbered the same from boot to boot. This inconsistency can cause serious system problems following a reboot. When installing CLE, the administrator must use persistent device names for file systems on the Cray system.

Cray recommends using the /dev/disk/by-id/ persistent device names. Use /dev/disk/by-id/ for the root file system in the initramfs image and in the /etc/sysset.conf installation configuration file as well as for other file systems, including Lustre (as specified in /etc/fstab and /etc/sysset.conf). For more information, see CLE Installation and Configuration Guide.

Alternatively, the administrator can define persistent names using a site-specific udev rule or cray-scsidev-emulation. However, only the /dev/disk/by-id method has been verified and tested.

CAUTION: The administrator must use /dev/disk/by-id when specifying the root file system. There is no support in the initramfs for cray-scsidev-emulation or custom udev rules.