Hi,

 

we are running an Unraid server since a few months and every once in a while there are some read-errors showing up in the System Log.

 

These are the errors:

Nov 22 13:57:40 Tower kernel: blk_update_request: I/O error, dev sdb, sector 2147483808 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Nov 22 13:57:40 Tower kernel: blk_update_request: I/O error, dev sdb, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 0

 

Those have happened since a while, and every time we have to rebuild the disk it seems. Now today we noticed that it may be due to the TimeMachine backup my Mac is running. I turned on my Mac at around 13:55 and just a few minutes later the errors show up.

 

Here's the relevant full log for that time frame, the read-errors are near the end:

 

Nov 22 13:56:44 Tower nginx: 2021/11/22 13:56:44 [alert] 3104#3104: worker process 4602 exited on signal 6
Nov 22 13:57:17 Tower kernel: sd 11:0:4:0: attempting task abort!scmd(0x0000000068b914ff), outstanding for 15487 ms & timeout 15000 ms
Nov 22 13:57:17 Tower kernel: sd 11:0:4:0: [sdf] tag#1344 CDB: opcode=0x85 85 06 20 00 00 00 00 00 00 00 00 00 00 40 e5 00
Nov 22 13:57:17 Tower kernel: scsi target11:0:4: handle(0x000c), sas_address(0x4433221106000000), phy(6)
Nov 22 13:57:17 Tower kernel: scsi target11:0:4: enclosure logical id(0x500605b009d32e70), slot(5) 
Nov 22 13:57:20 Tower kernel: sd 11:0:4:0: task abort: SUCCESS scmd(0x0000000068b914ff)
Nov 22 13:57:20 Tower kernel: sd 11:0:4:0: Power-on or device reset occurred
Nov 22 13:57:20 Tower emhttpd: read SMART /dev/sdf
Nov 22 13:57:21 Tower kernel: sd 11:0:4:0: Power-on or device reset occurred
Nov 22 13:57:37 Tower kernel: sd 11:0:0:0: attempting task abort!scmd(0x000000003808a1b1), outstanding for 15029 ms & timeout 15000 ms
Nov 22 13:57:37 Tower kernel: sd 11:0:0:0: [sdb] tag#1421 CDB: opcode=0x85 85 06 20 00 00 00 00 00 00 00 00 00 00 40 e5 00
Nov 22 13:57:37 Tower kernel: scsi target11:0:0: handle(0x000d), sas_address(0x4433221107000000), phy(7)
Nov 22 13:57:37 Tower kernel: scsi target11:0:0: enclosure logical id(0x500605b009d32e70), slot(4) 
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: task abort: SUCCESS scmd(0x000000003808a1b1)
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1388 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=0x08 cmd_age=16s
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1389 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=0x08 cmd_age=18s
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1388 Sense Key : 0x2 [current] 
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1388 ASC=0x4 ASCQ=0x0 
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1389 Sense Key : 0x2 [current] 
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1389 ASC=0x4 ASCQ=0x0 
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1388 CDB: opcode=0x35 35 00 00 00 00 00 00 00 00 00
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1389 CDB: opcode=0x88 88 00 00 00 00 00 80 00 00 a0 00 00 00 08 00 00
Nov 22 13:57:40 Tower kernel: blk_update_request: I/O error, dev sdb, sector 2147483808 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Nov 22 13:57:40 Tower kernel: blk_update_request: I/O error, dev sdb, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 0
Nov 22 13:57:40 Tower kernel: md: disk0 read error, sector=2147483744
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1390 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=0x08 cmd_age=0s
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1390 Sense Key : 0x2 [current] 
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1390 ASC=0x4 ASCQ=0x0 
Nov 22 13:57:40 Tower kernel: sd 11:0:0:0: [sdb] tag#1390 CDB: opcode=0x88 88 00 00 00 00 02 00 3a 67 88 00 00 00 08 00 00
Nov 22 13:57:40 Tower kernel: blk_update_request: I/O error, dev sdb, sector 8593762184 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Nov 22 13:57:40 Tower kernel: md: disk0 read error, sector=8593762120
Nov 22 13:57:40 Tower emhttpd: read SMART /dev/sdb
Nov 22 13:57:40 Tower emhttpd: read SMART /dev/sdc

 

 

Time Machine backup is on /dev/sdf, the disk where the read error occurs on (/dev/sdb) is one of the two parity drives.

 

sdb, sdc = Parity drives

sdd, sde, sdf = Storage drives

 

Does anyone have an idea what the cause and solution for this problem is?

Any more information I can provide to help figure out the issue?

 

Any help would be much appreciated!

There would be more context if you can share your diagnostics.