xfs_db: 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/xfs_db - from package: xfsprogs

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

On Debian possible default full paths are:

/usr/sbin/xfs_db - from package: xfsprogs

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

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