Spotted this today on bast3002, sdb is extremely slow and broken, hasn't been kicked out of the array yet though by mdadm
[10660197.262622] ata2: EH complete [10660199.576662] ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 [10660199.583362] ata2.00: BMDMA stat 0x24 [10660199.587195] ata2.00: failed command: READ DMA EXT [10660199.592156] ata2.00: cmd 25/00:08:20:0a:1d/00:00:13:00:00/e0 tag 0 dma 4096 in res 51/40:00:20:0a:1d/40:00:13:00:00/e0 Emask 0x9 (media error) [10660199.607631] ata2.00: status: { DRDY ERR } [10660199.611893] ata2.00: error: { UNC } [10660199.789271] ata2.00: configured for UDMA/133 [10660199.789293] sd 1:0:0:0: [sdb] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [10660199.789298] sd 1:0:0:0: [sdb] tag#0 Sense Key : Medium Error [current] [descriptor] [10660199.789302] sd 1:0:0:0: [sdb] tag#0 Add. Sense: Unrecovered read error - auto reallocate failed [10660199.789307] sd 1:0:0:0: [sdb] tag#0 CDB: Read(10) 28 00 13 1d 0a 20 00 00 08 00 [10660199.789310] blk_update_request: I/O error, dev sdb, sector 320670240 [10660199.795934] ata2: EH complete [10660199.819545] md/raid1:md2: read error corrected (8 sectors at 221059616 on sdb3) [10660202.044363] ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 [10660202.051057] ata2.00: BMDMA stat 0x24 [10660202.054893] ata2.00: failed command: READ DMA EXT [10660202.059857] ata2.00: cmd 25/00:08:28:0a:1d/00:00:13:00:00/e0 tag 0 dma 4096 in res 51/40:00:28:0a:1d/40:00:13:00:00/e0 Emask 0x9 (media error) [10660202.075303] ata2.00: status: { DRDY ERR } [10660202.079571] ata2.00: error: { UNC } [10660202.256640] ata2.00: configured for UDMA/133 [10660202.256659] sd 1:0:0:0: [sdb] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [10660202.256664] sd 1:0:0:0: [sdb] tag#0 Sense Key : Medium Error [current] [descriptor] [10660202.256668] sd 1:0:0:0: [sdb] tag#0 Add. Sense: Unrecovered read error - auto reallocate failed [10660202.256673] sd 1:0:0:0: [sdb] tag#0 CDB: Read(10) 28 00 13 1d 0a 28 00 00 08 00 [10660202.256675] blk_update_request: I/O error, dev sdb, sector 320670248 [10660202.263329] ata2: EH complete [10660202.304770] md/raid1:md2: read error corrected (8 sectors at 221059624 on sdb3) [10660202.304785] md/raid1:md2: redirecting sector 220797440 to other mirror: sda3