> Is this a Barracuda? ummmm :-( > Are you running that script that fixes timeouts? I am now: /dev/sda is bad Device Model: ST2000DM001-1ER164 /dev/sdb is bad /dev/sdc is good Device Model: ST31500341AS /dev/sdd is bad /dev/sde is bad /dev/sdf is good Device Model: ST31500341AS > When you get things sorted, you need to check all the SMARTs. Now I'm seeing this in the logs: Jun 9 15:51:31 ourserver kernel: md: recovery of RAID array md0 Jun 9 15:51:31 ourserver kernel: md/raid10:md0: insufficient working devices for recovery. Jun 9 15:51:31 ourserver kernel: md: md0: recovery interrupted. Jun 9 15:51:31 ourserver kernel: md: super_written gets error=10 Jun 9 15:53:23 ourserver kernel: program smartctl is using a deprecated SCSI ioctl, please convert it to SG_IO And trying to fail /dev/sdb results in: mdadm --manage /dev/md0 --fail /dev/sdb1 mdadm: set device faulty failed for /dev/sdb1: Device or resource busy Resync is now showing 0%: mdadm --detail /dev/md0 /dev/md0: Version : 1.2 Creation Time : Fri Mar 13 16:46:35 2020 Raid Level : raid10 Array Size : 2930010928 (2794.28 GiB 3000.33 GB) Used Dev Size : 1465005464 (1397.14 GiB 1500.17 GB) Raid Devices : 4 Total Devices : 4 Persistence : Superblock is persistent Update Time : Tue Jun 9 15:49:41 2020 State : clean, degraded, recovering Active Devices : 3 Working Devices : 4 Failed Devices : 0 Spare Devices : 1 Layout : near=2 Chunk Size : 8K Consistency Policy : resync Rebuild Status : 0% complete Name : ourserver:0 (local to host ourserver) UUID : 88b9fcb6:52d0f235:849bd9d6:c079cfc8 Events : 1081374 Number Major Minor RaidDevice State 0 8 81 0 active sync set-A /dev/sdf1 4 8 33 1 active sync set-B /dev/sdc1 3 8 17 2 active sync set-A /dev/sdb1 5 8 1 2 spare rebuilding /dev/sda1 - 0 0 3 removed cat /proc/mdstat Personalities : [raid10] md0 : active raid10 sda1[5](S)(R) sdf1[0] sdb1[3] sdc1[4] 2930010928 blocks super 1.2 8K chunks 2 near-copies [4/3] [UUU_] How do I promote the spare drive and fail /dev/sdb?