Dell Force10 E600i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 1092

www.dell.com | support.dell.com Parity error detection and correction There are two types of parity errors: transient and real. • Transient Parity Error- implies that a read value was corrupted in transit but that the actual memory may not be corrupt. Transient errors are further categorized as a recoverable and phantom. • Recoverable Transient Parity Error-a transient parity error indicated by SRAM that FTOS was able to correct (rewrite). • Phantom Transient Parity Error-a recoverable parity error for which the software was unable to determine a problem location. • Non-recoverable Error-implies a persistent corrupted memory location for which the only means of recovery is to reboot the line card. FTOS has the ability determine the error type when a parity error occurs and correct recoverable transient parity errors using the Parity Error Correction feature. During the SRAM scanning function, anytime the system detects a parity error, it must determine which type it is. To distinguish between the two types of parity errors (transient and non-recoverable), the system maintains a copy of all SRAM writes. If a location does not match the SRAM copy or causes another parity error indication in the status register, the system rewrites the location. After rewriting the location, the system again reads the location and checks the status register for parity error indication. If the location fails either of these two tests after a rewrite, then the parity error is non-recoverable, the location is marked as corrupt, and FTOS generates log messages. If the location passes these tests, then the parity error is transient (recoverable), the location is marked as having had a transient parity error, and FTOS continues the scan to the end of the SRAM bank. Enable parity error correction Parity Error Correction is disabled by default and consumes 25 megabytes of line card memory when you you enable it. To enable Parity Error Correction: Step 1 2 3 Task Verify that the line card has sufficient memory to enable this feature, as shown in the example below. Enable Parity Error Correction Reload the linecard. Command show processes memory lp Command Mode EXEC Privilege hardware monitor linecard asic fpc parity-correction reset linecard CONFIGURATION EXEC Privilege FTOS displays Message 8 on the console, when you enable Parity Error Correction. FTOS also records the messages in Message 9 in the trace log when you enable and disable Parity Error Correction, or insert a line card with Parity Error Correction enabled. 1092 | E-Series TeraScale Debugging and Diagnostics