IBM SAN256B-6, Installation, Service And User Manual, Page: 180 / 292

Replacing WWN cards (hot-swap)
Use this procedure to replace WWN cards with system power on. You can use this procedure to replace
one WWN card assembly at a time while power is on. To replace both cards, follow all steps for one card,
and then repeat the same steps to replace the other card assembly.
1. Save settings and system data and order replacement WWN card(s) by following all steps under
“Preparing for WWN card replacement” on page 153.
2. Replace a card by following all steps under “Hot-swap replacement” on page 154. Repeat these steps
to replace the second WWN card if necessary.
3. If RASlog messages indicate a mismatch between fan and system airflow direction, follow steps under
“Configuring airflow direction on WWN cards” on page 158.
4. Verify WWN card operation using steps under “Verifying WWN card operation” on page 160.
Replacing WWN cards (cold-swap)
Use this procedure to replace WWN cards with system power off. You can use this procedure to replace
one or both WWN cards.
1. Save settings and system data and order replacement WWN card(s) by following all steps under
“Preparing for WWN card replacement” on page 153.
2. Replace card(s) by following all steps under “Cold-swap replacement” on page 156.
3. If RASlog messages indicate a mismatch between fan and system airflow direction, follow steps under
“Configuring airflow direction on WWN cards” on page 158.
4. Verify WWN card operation using steps under “Verifying WWN card operation” on page 160.
Time and items required for replacement
If there is a need to replace one or both WWN cards, allow approximately 20 minutes. Refer to “Using
the wwnrecover utility” and “WWN card fault indicators” on page 150 before replacement.
The following items are needed to replace the WWN cards:
v Electrostatic discharge (ESD) grounding strap
v #1 Phillips screwdriver
v Workstation computer
Using the wwnrecover utility
The wwnrecover utility permits a recovery of WWN card data in the event of corruption. Recovery is not
possible if hardware issues prevent access to either WWN card or if the primary and backup copy of the
license ID on either card is corrupted.
Identical data must be maintained on each WWN card at all times so that if one card fails, the system can
use the other card to provide valid system operation. To maintain data and ensure its integrity, the
system audits both WWN cards one hour after the first system boot-up, every 24 hours after boot-up, and
any time a WWN card is inserted to compare the critical data.
If a data mismatch is detected during the audit, messages in the RASlog will provide a summary of all
errors detected and prompt you through a data recovery process. The data recovery mechanism may vary
depending on the error encountered and the data being compared. Problems such as a mismatch between
license IDs cannot be fixed with
wwnrecover
, and the output will direct you to call Technical Support. For
other problems, running
wwnrecover
can pinpoint the problem and, in some cases, permit you to fix it.
Mismatched data can be resolved, and corrupt data can sometimes be recovered.
The following table lists RASlog messages that can occur during the WWN card audit routine.
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SAN256B-6 Installation, Service, and User Guide