EMC Symmetrix DMX-3 User Manual

Reliability and availability features
163
Data Integrity, Availability, and Protection
Channel director
redundancy
Channel director redundancy is provided by configuring multiple
connections from the host servers (direct connect) or Fibre Channel
switch (SAN Connect) to the Symmetrix system. With SAN
connectivity, through Fibre Channel switches, each Symmetrix
DMX-3 port can support multiple host attachments, enabling storage
consolidation across a large number of host platforms. The multiple
connections are distributed across separate channel directors to
ensure uninterrupted access in the event of a channel failure. A
minimum of two connections per server or SAN is required to
provide full redundancy. Table 27 on page 163 defines the number of
host/SAN connections available for the Symmetrix DMX-3 system.
Channel failover functionality is required to automate the failover
and fail back process to avoid an interruption to data access.
Without this functionality, a path failure due to a problem with the
host bus adapter, Fibre Channel switch, fibre cable, or channel
director would create the potential for the application to go down.
EMC PowerPath provides this functionality and supports end-to-end
(host-to-switch and switch-to-storage) channel failover functionality.
PowerPath provides automatic, nondisruptive failover capabilities by
redirecting I/Os from a failed channel to all remaining channels for
open systems devices. PowerPath can automatically detect when a
path has failed and sends an error log to the host to notify it that there
is an inactive path.
Table 27 Symmetrix DMX-3 channel director connectivity
Protocol
a
Usable system ports
b
Ports per channel director
4 Gb/s Fibre Channel Host/SAN ports 2-64 1-8 per Fibre Channel Director
2 Gb/s Fibre Channel remote replication ports 2-8 1-4 per Fibre Channel Director
1 Gb/s iSCSI ports 2-32 1-4 per Multiprotocol Channel Director
1 Gb/s GigE remote replication ports 2-8 1-4 per Multiprotocol Channel Director
1 Gb/s GigE IPv4/v6 (IPsec capable) 2-8 1-4 per Multiprotocol Channel Director
4 Gb/s FICON host ports 2-32 1-4 per Multiprotocol Channel Director
ESCON host ports 2-80 1-8 per ESCON Director
ESCON remote replication ports 2-8 1-8 per ESCON Director
a. Contact your local EMC Sales Representative for ESCON channel director and GigE Remote support availability.
b. Usable ports are per qualified channel directors.

EMC Symmetrix DMX-3 Specifications

General

Brand	EMC
Model	Symmetrix DMX-3
Category	Storage
Language	English