IBM TotalStorage DS4800, Инструкция по установке, эксплуатации и обслуживанию

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4. If there are three or fewer EXP710s to be connected to a channel, then they
should all be daisy-chained together to one channel port on the channel. The
other channel port should be left unconnected.
5. If you are mixing EXP710s and EXP100s, all EXP710s must be grouped
together and all EXP100s must be grouped together.
6. It is recommended that you add storage expansion enclosures to the DS4800
drive ports in a round-robin fashion. For example, if you have four EXP810s to
be cabled to the DS4800, instead of cabling all four EXP810s to one drive port
of a drive channel, distribute the enclosures to all drive ports, which results in
one enclosure per drive port of a drive channel.
7. Do not connect more than the recommended maximum number of enclosures
per drive channel (eight for 14-drive and seven for 16-drive enclosures). When
mixing 14-drive and 16-drive enclosures, the maximum number of expansion
enclosures is seven per redundant drive channel pair.
8. DS4800 supports storage expansion enclosures operating at different fibre
channel speeds (for example, 2 Gbps or 4 Gbps) only when they are installed
in separate redundant drive channel pairs. DS4800 does not support a mix of
storage expansion enclosures operating at different fibre channel speeds in the
same redundant drive channel pair.
9. DS4800 supports a mix of EXP100, EXP710, and EXP810 storage expansion
enclosures in the same redundant drive channel pair. If possible, it is
recommended that you cable the storage expansion enclosures of the same
type together to ease maintenance and troubleshooting in the event of failures.
For specific cabling rules and restrictions when intermixing EXP100, EXP710,
and EXP810 storage expansion enclosures, see “One DS4800 to two or more
storage expansion enclosures in a mixed environment” on page 81.
10. The DS4000 controller drive port must always be connected to the EXP810
port labeled 1B. Because the left and right EXP810 ESMs (ESMs A and B) are
inserted in the ESM bays in different orientations, you must look for the port
labeled 1B before making the fibre channel connections.
11. Table 16 indicates a number of ways that four storage expansion enclosures
can be attached to the DS4800 controller drive ports. Case 7 is the
recommended way. Depending on your need and the type of storage
expansion enclosures that you used, you may also choose one of the other
ways described in the table. For example, in a given drive channel, you can
connect three storage expansion enclosures to the first port and five storage
expansion enclosures to the second port, or you can connect four storage
expansion enclosures to the first port and four storage expansion enclosures to
the second port. You cannot connect three storage expansion enclosures to
the first port and six storage expansion enclosures to the second port or one
storage expansion enclosure to the first port and eight storage expansion
enclosures to the second port; in these cases, the total number of storage
expansion enclosures connected to a single drive channel is greater than eight.
Table 16. Different ways to connect four storage expansion enclosures to the DS4800
Drive Channel 1
port 4
Drive Channel 1
port 3
Drive Channel 2
port 2
Drive Channel 2
port 1
Case 1 4 0 0 0
Case 2 3 1 0 0
Case 3 0 3 1 0
Case 4 2 2 0 0
Case 5 0 2 2 0
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IBM System Storage DS4800 Storage Subsystem: Installation, User’s, and Maintenance Guide
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