Most SATA drives behind a MegaRAID controller respond seamlessly to the -d megaraid,N flag.
The primary cause of this error is the way the MegaRAID controller manages disks. When a disk is part of a RAID array, the MegaRAID controller presents a virtual disk to the operating system, hiding the individual physical disks. As a result, smartctl cannot access the physical disk's SMART data directly.
When disks are connected through such a controller, the Linux kernel does not see the individual physical drives. Instead, it only sees the , the RAID volume presented as /dev/sda , /dev/sdb , etc. When you run smartctl -i /dev/sda , the command is essentially trying to query that virtual drive, which doesn't have a SMART interface to report, triggering the error: Most SATA drives behind a MegaRAID controller respond
To use the correct N value, you first need to identify the (DID) assigned by the controller.
Look for the DID (Device ID) or PD ID column – those numbers are your N values. As a result, smartctl cannot access the physical
for d in 0 1 2 3; do smartctl -H -d megaraid,$d /dev/sda; done
/dev/bus/0 -d megaraid,0 # /dev/bus/0 [megaraid_disk_00], SCSI device /dev/bus/0 -d megaraid,1 # /dev/bus/0 [megaraid_disk_01], SCSI device Use code with caution. When you run smartctl -i /dev/sda , the
Because these IDs do not always start sequentially at 0 (they often start at 32 , =0 , or vary based on enclosure cabling), you must first find the valid IDs. Run the built-in scan utility: smartctl megaraid,N ( how to find the right value for N ? )
Once installed, list all physical drives to see their Device IDs.
Note: Replace 0 with the actual Device ID you found in Step 1. In some configurations, the device node may also be /dev/bus/0 instead of /dev/sda . Why standard commands fail : Controllers like the Dell PERC H730 Go to product viewer dialog for this item.
This happens because the controller hides the physical drives and presents them as a "Virtual Drive" to the operating system. The smartctl command tries to speak directly to /dev/sda (the SCSI virtual drive), but the RAID controller interrupts, not knowing how to translate standard SMART commands to the underlying physical disks. The Solution: Using -d megaraid,N