by SHER

SMART monitoring for Synology NAS via SNMP. Creates one service per disk (named by drive bay, incl. expansion units) and alerts on DSM-reported attribute failures plus rising pre-failure counters: reallocated, pending, and uncorrectable sectors, and UDMA CRC errors. Thresholds adjustable per service via an optional rule set. Validated on DSM 6.2, 7.0 and 7.1+.