Sun Microsystems StorEdge 3000 Series, Руководство по лучшим практикам

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14 Sun StorEdge 3000 Family Best Practices Manual • March 2007
Configuring an Array’s RCCOM
Channel
Redundant controller communication (RCCOM) provides the communication
channels by which two controllers in a redundant RAID array communicate with
one another. This communication allows the controllers to monitor each other, and
includes configuration updates, and control of cache. By default, channels 2 and 3
are configured as DRV + RCCOM (Drive and RCCOM). In this configuration,
RCCOM is distributed over all DRV + RCCOM channels. However, when host
channels remain unused two alternative configurations are available. Refer to the
Sun StorEdge 3000 Family RAID Firmware User’s Guide for your array to see step-by-
step procedure for reconfiguring RCCOM channels.
Using Four DRV + RCCOM Channels
If only channels 0 and 1 are used for communication with servers, channels 4 and 5
can be configured as DRV + RCCOM, providing four DRV + RCCOM channels
(channels 2, 3, 4 and 5). An advantage of this configuration is channels 4 and 5 are
still available for connection of expansion units. The impact of RCCOM is reduced
because it is now distributed over four channels instead of two. If at a later time you
choose to add an expansion unit, it will not be necessary to interrupt service by
resetting the controller after reconfiguring a channel.
Using Channels 4 and 5 as RCCOM Channels
When only channels 0 and 1 are used for communication with servers, another
option is to assign channels 4 and 5 as dedicated RCCOM channels. This reduces the
impact of RCCOM on the drive channels by removing RCCOM from drive channels
2 and 3. In this configuration, however, channels 4 and 5 cannot be used to
communicate with hosts or to attach expansion modules.