ctdb_persistent: 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 Debian possible default full paths are:

/usr/lib/ctdb/tests/bin/ctdb_persistent - from package: ctdb-dbg

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

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