xfs_check: command not found

Have You tried accessing the binary with the full path?

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_check - from package: xfsprogs

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