Smartctl Open Device Dev Sda Failed Dell Or Megaraid Controller Please Try Adding 39d Megaraid N 39 Extra Quality May 2026

smartctl open device: /dev/sda failed: DELL or MegaRAID controller, please try adding -d megaraid,N This message appears because smartctl (part of the smartmontools package) expects to communicate directly with a physical disk. However, a RAID controller presents a (e.g., /dev/sda , /dev/sdb ) to the operating system. The OS sees only the logical array, not the individual physical disks behind the controller. To get S.M.A.R.T. data from each physical drive, you must bypass this virtualization using the -d megaraid,N flag.

PD LIST : ======= EID:Slt DID State DG Size Intf Med 16:0 0 Onln 0 1.818 TB SATA HDD 16:1 1 Onln 0 1.818 TB SATA HDD Here, DID column gives 0 and 1 as physical drive numbers. Sometimes helpful for direct-attached drives, but less so behind RAID. Try: smartctl open device: /dev/sda failed: DELL or MegaRAID

Example output snippet:

SMART Health Status: OK smartctl -A -d megaraid,1 /dev/sda Test background self-check on disk 3 smartctl -t short -d megaraid,2 /dev/sda View all S.M.A.R.T. info for disk 0 smartctl -a -d megaraid,0 /dev/sda What if you have multiple logical drives? If your controller presents multiple logical drives ( /dev/sda , /dev/sdb , /dev/sdc ), then /dev/sda may contain physical disks with IDs 0,1,2 and /dev/sdb may contain physical disks with IDs 3,4,5. The N value is controller-wide , not per logical drive. So you can usually access all physical disks through any logical device, but safest is to use the logical drive that belongs to the same RAID group. When in doubt, try all N on /dev/sda . To get S