scsi_ready: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/scsi_ready - from package: sg3-utils

You may install the required package with command apt-get install {package}
Error in other languages:
scsi_ready: bevel nie gevind nie
scsi_ready: comandă negăsită
scsi_ready: comando não encontrado
scsi_ready: commande introuvable
scsi_ready: command not found
scsi_ready: käsku ei ole
scsi_ready: không tìm thấy lệnh
scsi_ready: komanda nerasta
scsi_ready: Kommando nicht gefunden.
scsi_ready: kommandot finns inte
scsi_ready: komut yok
scsi_ready: nie znaleziono polecenia
scsi_ready: níor aimsíodh an t-ordú
scsi_ready: no se encontró la orden
scsi_ready: no s'ha trobat l'ordre
scsi_ready: opdracht niet gevonden
scsi_ready: parancs nem található
scsi_ready: perintah tidak ditemukan
scsi_ready: príkaz nenájdený
scsi_ready: příkaz nenalezen
scsi_ready: команда не найдена
scsi_ready: командата не е открита
scsi_ready: 命令找不到
scsi_ready: コマンドが見つかりません