xfsdump: 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/xfsdump - from package: xfsdump
/usr/sbin/xfsdump - from package: xfsdump

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

On Debian possible default full paths are:

/sbin/xfsdump - from package: xfsdump
/usr/sbin/xfsdump - from package: xfsdump

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

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