Users Guide
Battery Transparent Learn Cycle
A transparent learn cycle is a periodic operation that calculates the charge that is remaining in the battery to ensure there is sucient
energy. The operation runs automatically, and causes no impact to the system or Shared PERC 8 card performance. The Shared PERC 8
card automatically performs the Transparent Learn Cycle (TLC) on the battery to calibrate and gauge its charge capacity once every 90
days.
NOTE: Virtual disks stay in Write-Back mode, if enabled, during transparent learn cycle. If the TLC completes, the Shared PERC
8 card sets the next TLC to +90 days.
TLC time frame
The time frame for completion of a learn cycle is a function of the battery charge capacity and the discharge and charge currents used. For
the Shared PERC 8 card, the expected time frame for completion of a learn cycle is approximately seven hours.
Conditions for replacing the battery
The Shared PERC 8 battery is marked Failed in the Battery Status in the CMC, when the state or health of the battery is declared bad. If
battery is declared failed, then the rmware runs learn cycles in subsequent reboots until the battery is replaced. After the battery is
replaced, the virtual disk then transitions to write-back mode.
The controller failover feature
The dual-controller conguration of the VRTX system has two shared-PERC controllers congured in an active-passive mode. A single
active controller is responsible for all the storage related processes. When the active controller stops functioning, the passive controller acts
as a hot-spare, and takes over the functions of the active controller.During a controller failover, there may be some temporary performance
impact in the course of the failover.
Multipath support
Multipathing solutions use redundant physical path components such as adapters, cables, and switches to create logical paths between the
server and the storage device. When one or more of these components fails, multipathing logic uses an alternate path for I/O so that
applications can still access their data.
In the Fault Tolerant Shared PERC 8 card conguration, the PowerEdge VRTX system has two Shared PERC 8 cards in an active-passive
mode. In this conguration, each host server can access the same virtual disk through both cards. In the absence of a multipath driver, the
operating system identies the single disk as two identical disks. The multipath driver aggregates the two disks into a single disk with
redundant access that is then presented to the operating system. The operating system’s multipath functionality determines the path
chosen for any I/O sent to the virtual disk. Any I/O directed to the passive card is internally redirected to the active card for completion.
For instructions on how to set up multipath for supported operating systems, see Multipath and clustering setup.
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Shared PERC 8 card features