A solução geral para esse problema é adicionar os discos por id (s), ou seja,
ls -l /dev/disk/by-id | grep sda | head -n1
ls -l /dev/disk/by-id | grep sdb | head -n1
E você verá ponteiros para os discos. No meu sistema, ls -l /dev/disk/by-id | grep sda
yields -
$ ls -l /dev/disk/by-id | grep sda
lrwxrwxrwx 1 root root 9 Apr 19 15:36 ata-ST95005620AS_5YX07EY0 -> ../../sda
lrwxrwxrwx 1 root root 10 Apr 19 15:36 -> ../../sda1
lrwxrwxrwx 1 root root 10 Apr 19 15:36 ata-ST95005620AS_5YX07EY0-part2 -> ../../sda2
lrwxrwxrwx 1 root root 10 Apr 19 15:36 ata-ST95005620AS_5YX07EY0-part5 -> ../../sda5
lrwxrwxrwx 1 root root 9 Apr 19 15:36 scsi-SATA_ST95005620AS_5YX07EY0 -> ../../sda
lrwxrwxrwx 1 root root 10 Apr 19 15:36 scsi-SATA_ST95005620AS_5YX07EY0-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 Apr 19 15:36 scsi-SATA_ST95005620AS_5YX07EY0-part2 -> ../../sda2
lrwxrwxrwx 1 root root 10 Apr 19 15:36 scsi-SATA_ST95005620AS_5YX07EY0-part5 -> ../../sda5
lrwxrwxrwx 1 root root 9 Apr 19 15:36 wwn-0x5000c5002aa74475 -> ../../sda
lrwxrwxrwx 1 root root 10 Apr 19 15:36 wwn-0x5000c5002aa74475-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 Apr 19 15:36 wwn-0x5000c5002aa74475-part2 -> ../../sda2
lrwxrwxrwx 1 root root 10 Apr 19 15:36 wwn-0x5000c5002aa74475-part5 -> ../../sda5
O seu será diferente, mas por exemplo /dev/sda1
; Eu adicionaria -
/dev/disk/by-id/ata-ST95005620AS_5YX07EY0-part1