fence_scsi: command not found

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

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

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 CentOS possible default full paths are:

/usr/sbin/fence_scsi - from package: fence-agents

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/fence_scsi - from package: fence-agents

You may install the required package with command apt-get install {package}

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