I have a server with 2 internal disks with Adaptec hardware RAID and an external disk box connected via SAS.
lsscsi finds all the devices:
# lsscsi [0:0:0:0] disk Adaptec System V1.0 /dev/sda [0:1:0:0] disk WDC WD1003FBYX-0 01.0 - [0:1:1:0] disk WDC WD1003FBYX-0 01.0 - [1:0:0:0] disk Promise VessRAID 1840s 0304 -
The first 3 are the 2 physical disks and the hardware RAID on top of those.
The 4th is the external diskbox connected via SAS.
As you can see there is no corresponding device in /dev for the external VessRAID.
The VessRAID is an external SAS-RAID box that presents itself as a SAS device. Linux clearly sees the device, but somehow it does not make it into a device in /dev.
There are two logical drives on the VessRAID.
I have the feeling I need to tell Linux that this is a SAS disk device that Linux should use and scan for logical drives and make them show up in /dev. But I have been unable to find the the magical command that does this.
/sys gave this:
# cat /sys/class/bsg/1\:0\:0\:0/device/model VessRAID 1840s # cat /sys/class/bsg/1\:0\:0\:0/device/vendor Promise
Again this confirms that Linux sees the device, which is already known.
/dev/disk/* sees the RAID'ed internal disks as one device with 2 partition. It does not see the external disk:
# ls -al /dev/disk/by-path total 0 drwxr-xr-x 2 root root 100 Jun 29 17:06 . drwxr-xr-x 5 root root 100 Jun 29 17:06 .. lrwxrwxrwx 1 root root 9 Jun 29 17:06 pci-0000:02:00.0-scsi-0:0:0:0 -> ../../sda lrwxrwxrwx 1 root root 10 Jun 29 17:06 pci-0000:02:00.0-scsi-0:0:0:0-part1 -> ../../sda1 lrwxrwxrwx 1 root root 10 Jun 29 17:06 pci-0000:02:00.0-scsi-0:0:0:0-part2 -> ../../sda2