This error occurs when smartctl cannot directly access a physical disk (/dev/sda) because the disk is behind a Dell PERC or MegaRAID controller. The OS sees a virtual drive, not the raw physical disk.
"smartctl open device dev sda failed dell or megaraid controller please try adding -d megaraid,N" This error occurs when smartctl cannot directly access
The error smartctl open device: /dev/sda failed: DELL or MegaRAID controller, please try adding -d megaraid,N is not a bug—it is a sign that you need to tell smartctl which physical drive behind the RAID controller to query. This error occurs because the LSI MegaRAID controller
This applies to any LSI MegaRAID card (e.g., 9260, 9361) under Linux. For HP SmartArray, use -d cciss,N; for 3ware, use -d 3ware,N. 9361) under Linux. For HP SmartArray
This error occurs because the LSI MegaRAID controller hides physical drives behind a virtual RAID volume . To access individual drive health data, you must tell which specific physical slot to query.