Dell PowerVault 775N (Rackmount NAS Appliance) - Manual (Page 24)

Figure 2-6. Important System Warning
The warning message appears on the screen immediately after activating the PERC BIOS configuration utility by pressing
during the system's POST and when you attempt to perform a data-destructive operation in the Dell™
PowerEdge™ RAID Console utility. Examples of data-destructive operations include clearing the configuration of the logical
drives or changing the RAID level of your shared hard drives.
This warning message alerts you to the possibility of data loss if certain precautions are not taken to protect the integrity of
the data on your cluster.
NOTICE: To prevent data loss, your cluster must meet the conditions in the following bulleted list before you attempt
any data-destructive operation on your shared hard drives.
Ensure that the peer system is turned on during the operation so that the PERC card's NVRAM can be updated with the
new configuration information. Alternately, if the peer system is down, you must save the disk configuration to the
shared storage system. When you restart the system later, update the peer system's NVRAM from the disk
configuration saved to the shared storage system.
Ensure that the peer cluster node is not currently configuring the shared storage system.
Ensure that I/O activity does not occur on the shared storage system during the operation.
Ensure that your PERC firmware is the latest version. See your PERC documentation for information on downloading the
latest firmware.
Enabling the Cluster Mode Using the PERC Card
Each PERC card that is used to connect to a shared storage enclosure must have cluster mode enabled using the PERC card's
BIOS configuration utility. Enabling cluster mode implements the additional functionality required for the controller to operate
in a cluster environment.
See Table 2-3 for more information on split-bus module modes.
NOTICE: If you replace your PERC card, ensure that you enable the cluster mode on the replacement PERC card and
set the SCSI ID to the appropriate value (6 or 7) before you connect the SCSI cables to the shared storage.
See the appropriate PERC card documentation for more information about enabling cluster mode and the SCSI host adapter.