DIMMs
Dual in-line memory modules (DIMMs) supply the random-access memory (RAM) for Unity. In cases of
failure, they can be replaced.
Note
A failed DIMM affects the entire controller, but replacement of a DIMM can only be done by Nexsan
Support Group. Please contact Nexsan Support immediately if you suspectz a failed DIMM in your Unity
Storage Systems.
Identifying a failed DIMM
DIMM failure can be difficult to diagnose without the assistance of Nexsan Support; however, the following
may help you identify a potentially failed DIMM:
If you have autolog enabled, the analyzer will likely detect a failed DIMM.
If you are familiar with the amount of RAM that you have, run the
top
command in the command line
interface (CLI) to see if the amount is lower than you think it should be. See
Accessing the nxadmin CLI
and
Using the nxadmin CLI’s command-based shell
in the
Unity CLI Reference Guide
. You can also check
if the amount of RAM is comparatively lower than the other controller.
A failed DIMM often causes a drop in the system's performance.
Note
It is possible for DIMMs to only partially fail. In this case, the
top
command in the nxadmin CLI may not
show lower RAM levels and there may not be a visible drop in performance. However, seemingly random
failures and system crashes will likely still occur and are important signs of DIMM failure.
If you suspect DIMM failure, contact Nexsan Support for assistance.
DIMMs
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Nexsan Unity Hardware Maintenance Guide v. 5.1
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