---
name: "mfsbdev.cfg"
section: "5"
platform: "linux"
package: "moosefs"
version: "4.59.2-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/mfsbdev.cfg"
---

# mfsbdev.cfg(5)

MooseFS block device daemon config file

## NAME

mfsbdev.cfg - **MooseFS** block device daemon config file

## DESCRIPTION

This is the config file that can be read by the **mfbsdev** tool if the **-i** option was  supplied along with the **start** command. The file contains definitions of block devices (one per line) that should be initialized  when **mfsbdev** tool is started.

It is strongly recommended to not create this file from scratch. Instead, it's best to create all the necessary devices using **mfsbdev** command and its parameters, as described in [**mfsbdev**(8)](/mfsbdev/8.md)  and then list them with the **mfsbdev list -i** command and use the output to create a config file. The following description is provided so it explains the content of the config file and allows to  adjust it if necessary.

### FORMAT

Empty lines and lines that start with a semicolon (**;**) or hash (**#**) sign are ignored. Every other  line should match the format:

*path* \[ *device*\|**\*** \[ *linkname*\|**\*** \[ *size*\|**\*** \[ *bsize*\|**\*** \[ *flags* \]\]\]\]\]

*path* information is obligatory and should be a path to a file on MooseFS that will be used as the block device; the path should be relative to MooseFS root or path defined with **-S** option when starting **mfsbdev**, not your local file system root

*device* information is optional, if supplied should point to a network block device path  (eg. /dev/nbd1); if not present or **\*** is supplied, first available block device will be used

*linkname* information is optional, if supplied should indicate the name of symbolic link  created in '/dev/mfs', pointing at the network block device created by the map command;  if not present or **\*** is supplied, default link name will be used

*size* information is optional, if supplied indicates block device size; if not present or **\*** is supplied,  the size of the file indicated by the first parameter is used

*bsize* information is optional, if supplied indicates block size; if not present or **\*** is supplied, 4096 bytes block is used

*flags* information is optional, can contain the following flags  (separated by comma if more than one is listed) **ro** - read only device, **rw** read/write device,  **lock** - device requires an appropriate type of lock (shared for **ro**, exclusive for **rw**), **nolock** - device does not require a lock (will try to obtain it, but will ignore failure);  if nothing is supplied, the default of **rw**, **lock** is assumed;  if two conflicting flags are supplied (i.e. **ro** and **rw** or **lock** and **nolock**) the last one wins

## EXAMPLES

Create read/write devices with default block device path, default linkname, using file size as  device size, with default block size:

**my\_devices/device1**

**my\_devices/device2 \* \* \* \* rw**

Create read only devices with specific parameters:

**my\_devices/device1 /dev/nbd3 mfsdevice1 67108864 1024 ro**

**my\_devices/device2 /dev/nbd7 mfsdevice2 64MiB 1024 ro,nolock**

## REPORTING BUGS

Report bugs to \<bugs@moosefs.com\>.

## COPYRIGHT

Copyright (C) 2026 Jakub Kruszona-Zawadzki, Saglabs SA

This file is part of MooseFS.

MooseFS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2 (only).

MooseFS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, see \<https://www.gnu.org/licenses/\>.

## SEE ALSO

[**mfsmount**(8)](/mfsmount/8.md), [**mfsbdev**(8)](/mfsbdev/8.md)