hesela.devSAS PHY event counters
SAS PHY event counters are per-physical-link-endpoint counts of specified link events, including invalid DWORDs, disparity errors, synchronization loss and PHY reset problems.
smartmontools 7.5 decodes four 32-bit counters in each SAS PHY descriptor: invalid DWORDs, running disparity errors, loss of DWORD synchronization and PHY reset problems; additional event descriptors may be present [1]. These observations are not media-error totals or root-cause labels, and reset problems are not a count of every reset. For supported SAS SSP devices, smartctl -l sasphy reads Protocol Specific log page 0x18 without requesting a counter reset; sasphy,reset reads first and then requests a reset [2]. Preserve initial output and the reset result. Interpretation guidance: compare the same device, port, PHY and reporting endpoint over a recorded interval. Reset, replacement or an unexplained decrease requires a new baseline; do not blindly assume wraparound. Events per hour are not a bit-error rate or drive-failure rate. Linux driver-exposed PHY statistics and target-device log counters are distinct observations and must not be silently combined [3]. Missing or unsupported telemetry is not a measured zero. Linux v6.12 may print a stored PHY value even when its acquisition callback is absent; successful reading alone does not establish freshness [3]. smartmontools uses positional JSON keys, not endpoint IDs, and separate read/reset commands, not an atomic read-and-clear [1]. The companion analysis explains the evidence boundaries [4].
Relations
- related
- sas, scsi
Limitations
- A nonzero count does not identify the faulty cable, backplane, controller or drive.
- Comparisons require endpoint identity and continuous counter history; collection support depends on device, controller and driver.