EMC Symmetrix DMX-3, Product Manual

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176 EMC Symmetrix DMX-3 Product Guide
Data Integrity, Availability, and Protection
To provide remote support capabilities, the Symmetrix system is
configured to phone home and alerts EMC Customer Support of a
failure or potential failure. The appropriate authorized EMC Product
Support Engineer is able to run system diagnostics remotely for
further troubleshooting and resolution. Configuring the EMC
products to allow inbound dial also enables EMC Customer Support
to proactively dial in to the Symmetrix system to gather needed
diagnostic data or to attend to identified issues. The current dial-in
support program for the Symmetrix system uses the latest digital key
exchange technology for strong authentication, layered application
security, and a centralized support infrastructure that places calls
through an encrypted tunnel between EMC Customer Support and
the service processor located inside the Symmetrix system.
Before any individual can initiate a call to a customer site, that person
must be individually authenticated and determined to be an
appropriate member of the EMC support team. Field-based
personnel who might be known to the customer must still be
properly associated with the specific customer’s account. An
essential part of the design of the dial-in support program is that the
call to the customer’s Symmetrix service processor must originate
from one of several specifically designed Remote Support Networks
at EMC. Within each of those EMC Support Centers, the necessary
networking and security infrastructure has been built to enable both
the call-EMC and call-device functions.
Error Checking and
Correction, and
data integrity
protection
In conventional DASD, the subsystem adds Error Checking and
Correction (ECC) bytes to each data record field, as shown in
Figure 40 on page 176 . The system uses these error checking and
correction bytes to check the data and correct it, if possible. If it
detects an uncorrectable error, the DASD subsystem informs the host
that it has encountered bad data to avoid affecting data integrity.
Figure 40 Data record format for conventional DASD
Symmetrix systems, like conventional DASD, perform this level of
error checking and correction when they pass data and addresses.
Symmetrix systems, however, go further to ensure that the
information passed belongs to the record specified. The system does
this by including additional bytes with the data field of each record.
Data record
ECC
bytes