As far as I can see, both disks are to storage the boot images sor for the Mobility Master.
/dev/sdb1 this is the files available in directory(we can check this by using the command: #dir)
/dev/sdb5 this is boot partition 0:0
/dev/sdb6 this is boot partition 0:1
(EU-WLAN-MM01) [mynode] #show storage
Filesystem Size Used Available Use% Mounted on
none 3.0G 28.9M 3.0G 1% /tmp
/dev/sdb1 5.8G 1.7G 3.8G 31% /flash
/dev/sda5 1.4G 381.3M 1021.7M 27% /mnt/disk1
/dev/sda6 1.4G 381.3M 1021.7M 27% /mnt/disk2
(EU-WLAN-MM01) [mynode] #
(EU-WLAN-MM01) [mynode] #show image
version Show System image version information
(EU-WLAN-MM01) [mynode] #show image version
----------------------------------
Partition : 0:0 (/mnt/disk1)
Software Version : ArubaOS 8.1.0.1 (Digitally Signed SHA1/SHA256 - Production Build)
Build number : 59688
Label : 59688
Built on : Thu May 18 20:22:32 UTC 2017
----------------------------------
Partition : 0:1 (/mnt/disk2) **Default boot**
Software Version : ArubaOS 8.1.0.2 (Digitally Signed SHA1/SHA256 - Production Build)
Build number : 60858
Label : 60858
Built on : Sun Aug 6 02:02:47 UTC 2017
(EU-WLAN-MM01) [mynode] #