lvscan: 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/lvscan - from package: lvm2

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

On Debian possible default full paths are:

/sbin/lvscan - from package: lvm2

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

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