From your syslog, your disk 11 is having READ and WRITE errors. Maybe it's your MPT3 SAS controller or cables? Not sure what more to look at/for, been ages since I looked at this sort of stuff, so out of practice. Hoping someone else can pickup the ball and continue the task. The SMART report seems to be when you were in process of performing an Extended Offline SMART test? SMART Extended Self-test Log Version: 1 (1 sectors) Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error # 1 Extended offline Self-test routine in progress 90% 11299 - Drive Identification: Apr 17 12:10:25 Unraid emhttpd: online: ST16000NM000J-2TW103_ZR553342 (sdn) 512 31251759104 Syslog error segment: Apr 24 00:24:14 Unraid kernel: mpt3sas_cm0: log_info(0x31110d00): originator(PL), code(0x11), sub_code(0x0d00) Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1543 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=DRIVER_OK cmd_age=0s Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1543 Sense Key : 0x2 [current] Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1543 ASC=0x4 ASCQ=0x0 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1543 CDB: opcode=0x88 88 00 00 00 00 07 0d 30 99 f0 00 00 00 20 00 00 Apr 24 00:24:14 Unraid kernel: I/O error, dev sdn, sector 30286060016 op 0x0:(READ) flags 0x0 phys_seg 4 prio class 0 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=30286059952 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=30286059960 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=30286059968 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=30286059976 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1544 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=DRIVER_OK cmd_age=4s Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1544 Sense Key : 0x2 [current] Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1544 ASC=0x4 ASCQ=0x0 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1544 CDB: opcode=0x88 88 00 00 00 00 01 07 65 79 68 00 00 00 80 00 00 Apr 24 00:24:14 Unraid kernel: I/O error, dev sdn, sector 4419058024 op 0x0:(READ) flags 0x0 phys_seg 16 prio class 0 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419057960 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419057968 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419057976 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419057984 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419057992 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058000 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058008 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058016 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058024 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058032 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058040 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058048 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058056 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058064 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058072 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419058080 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1559 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=DRIVER_OK cmd_age=0s Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1559 Sense Key : 0x2 [current] Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1559 ASC=0x4 ASCQ=0x0 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1559 CDB: opcode=0x8a 8a 00 00 00 00 01 07 65 79 68 00 00 00 28 00 00 Apr 24 00:24:14 Unraid kernel: I/O error, dev sdn, sector 4419058024 op 0x1:(WRITE) flags 0x0 phys_seg 5 prio class 0 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419057960 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419057968 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419057976 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419057984 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419057992 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1560 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=DRIVER_OK cmd_age=0s Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1560 Sense Key : 0x2 [current] Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1560 ASC=0x4 ASCQ=0x0 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1560 CDB: opcode=0x8a 8a 00 00 00 00 07 0d 30 99 f0 00 00 00 20 00 00 Apr 24 00:24:14 Unraid kernel: I/O error, dev sdn, sector 30286060016 op 0x1:(WRITE) flags 0x0 phys_seg 4 prio class 0 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=30286059952 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=30286059960 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=30286059968 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=30286059976 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1562 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=DRIVER_OK cmd_age=0s Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1562 Sense Key : 0x2 [current] Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1562 ASC=0x4 ASCQ=0x0 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1562 CDB: opcode=0x8a 8a 00 00 00 00 01 07 65 79 90 00 00 00 58 00 00 Apr 24 00:24:14 Unraid kernel: I/O error, dev sdn, sector 4419058064 op 0x1:(WRITE) flags 0x0 phys_seg 11 prio class 0 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058000 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058008 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058016 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058024 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058032 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058040 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058048 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058056 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058064 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058072 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419058080 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1563 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=DRIVER_OK cmd_age=0s Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1563 Sense Key : 0x2 [current] Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1563 ASC=0x4 ASCQ=0x0 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1563 CDB: opcode=0x88 88 00 00 00 00 01 07 6b 74 48 00 00 00 28 00 00 Apr 24 00:24:14 Unraid kernel: I/O error, dev sdn, sector 4419449928 op 0x0:(READ) flags 0x0 phys_seg 5 prio class 0 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419449864 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419449872 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419449880 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419449888 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=4419449896 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1567 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=DRIVER_OK cmd_age=0s Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1567 Sense Key : 0x2 [current] Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1567 ASC=0x4 ASCQ=0x0 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1567 CDB: opcode=0x88 88 00 00 00 00 01 92 80 99 c8 00 00 00 20 00 00 Apr 24 00:24:14 Unraid kernel: I/O error, dev sdn, sector 6752868808 op 0x0:(READ) flags 0x0 phys_seg 4 prio class 0 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=6752868744 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=6752868752 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=6752868760 Apr 24 00:24:14 Unraid kernel: md: disk11 read error, sector=6752868768 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1584 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=DRIVER_OK cmd_age=0s Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1584 Sense Key : 0x2 [current] Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1584 ASC=0x4 ASCQ=0x0 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1584 CDB: opcode=0x8a 8a 00 00 00 00 01 07 6b 74 48 00 00 00 28 00 00 Apr 24 00:24:14 Unraid kernel: I/O error, dev sdn, sector 4419449928 op 0x1:(WRITE) flags 0x0 phys_seg 5 prio class 0 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419449864 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419449872 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419449880 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419449888 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=4419449896 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1592 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=DRIVER_OK cmd_age=0s Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1592 Sense Key : 0x2 [current] Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1592 ASC=0x4 ASCQ=0x0 Apr 24 00:24:14 Unraid kernel: sd 11:0:4:0: [sdn] tag#1592 CDB: opcode=0x8a 8a 00 00 00 00 01 92 80 99 c8 00 00 00 20 00 00 Apr 24 00:24:14 Unraid kernel: I/O error, dev sdn, sector 6752868808 op 0x1:(WRITE) flags 0x0 phys_seg 4 prio class 0 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=6752868744 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=6752868752 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=6752868760 Apr 24 00:24:14 Unraid kernel: md: disk11 write error, sector=6752868768