vgscan: 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:

/sbin/vgscan - from package: lvm2

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

On Debian possible default full paths are:

/sbin/vgscan - from package: lvm2

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

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