Mnesia has no access to create table in disc macOs dev mode

Hello, I have read many posts about disc problem in the forum, but I have still this problem:

I have no problem to create ram copy

  {:aborted, {:bad_type, MishkaAuth.User.Users, :disc_copies, :nonode@nohost}}}}

I did this comment before creating a post:

my config file:

config :mnesia, dir: "/Users/shahryar/Desktop/D-Access/mnesia_db"
# drwxr-xr-x   3 shahryar  staff         96 Mar 22 15:04 mnesia_db

My fields and mnesia name:

  @mnesia_tab __MODULE__

  @mnesia_tab_fields [

And the function I create a disc_copies table

def start_mnesia() do

  |> IO.inspect(label: "Mnesia schema start of user ====>")

  |> IO.inspect(label: "Application start of user ====>")

  case :mnesia.create_table(@mnesia_tab,
          type: :set,
          disc_copies: [Node.self()],
          attributes: @mnesia_tab_fields,
          index: [:username, :email, :mobile],
          record_name: @mnesia_tab,
          storage_properties: [ets: [{:read_concurrency, true}, {:write_concurrency, true}]]
        ) do
    {:atomic, :ok} -> :ok
    {:aborted, {:already_exists, @mnesia_tab}} -> :ok
    any -> {:error, {:create_table, any}}
  |> IO.inspect(label: "Creating table ---->")

  :mnesia.wait_for_tables([@mnesia_tab], :timer.seconds(15))
  |> IO.inspect(label: "Mnesia wait for tables start of user ====>")

I am using mac os and dev mode with iex -S mix phx.server

Please help me to fix this issue, 3 or 4 years ago I fixed it, but I can not remember now :frowning:

Thank you in advance

I remove my custom path and it works, but I dont know why i can not set a dir for mnesia

for example if i set a path:

Application.put_env(:mnesia, :dir, "/Users/shahryar/Desktop/D-Access/mnesia_db")


Application.put_env(:mnesia, :dir, "/Users/shahryar/Desktop/D-Access/mnesia_db")

after that call


It returns {:error, {:EXIT, :function_clause}}

I do not know why


use this :rage: :rage: :rage: :rage: :rage: :rage:

Application.put_env(:mnesia, :dir, mnesia_dir |> to_charlist)
1 Like

:wink: :smile: :wink: :smile:
Yes, Mnesia is an old Erlang tool and in Erlang strings are charlists. That’s the way it is.


Yes, Thank you, it is as you say sir. But I went through a very hard way to remember that :joy: more than 5 hours :face_with_spiral_eyes: