Here, we explain how users can customize the runtime behavior of UnifyFS. In particular, UnifyFS provides the following ways to configure:
- Configuration file:
- Environment variables
- Command line options to
All configuration settings have corresponding environment variables, but only
certain settings have command line options. When defined via multiple methods,
the command line options have the highest priority, followed by environment
variables, and finally config file options from
The system-wide configuration file is used by default when available.
However, users can specify a custom location for the configuration file using
-f command-line option to
unifyfsd (see below).
There is a sample
unifyfs.conf file in the installation directory
etc/unifyfs/. This file is also available in the
in the source repository.
The unified method for providing configuration control is adapted from CONFIGURATOR. Configuration settings are grouped within named sections, and each setting consists of a key-value pair with one of the following types:
FLOAT: scalars convertible to C double, or compatible expression
INT: scalars convertible to C long, or compatible expression
STRING: quoted character string
The config file has several sections, each with a few key-value settings.
In this description, we use
section.key as shorthand for the name of
a given section and key.
|cleanup||BOOL||cleanup storage on server exit (default: off)|
|configfile||STRING||path to custom configuration file|
|daemonize||BOOL||enable server daemonization (default: off)|
|mountpoint||STRING||mountpoint path prefix (default: /unifyfs)|
cwd setting is used to emulate the behavior one
expects when changing into a working directory before starting a job
and then using relative file names within the application.
If set, the application changes its working directory to
the value specified in
unifyfs_mount() is called.
The value specified in
cwd must be within the directory space
of the UnifyFS mount point.
local_extents optimization may significantly improve read
performance for extents written by the same process. However, it should not
be used by applications in which different processes write to the same byte
offset within a file, nor should it be used with applications that truncate
|dir||STRING||path to directory to contain server log file|
|file||STRING||log file base name (rank will be appended)|
|on_error||BOOL||increase log verbosity upon encountering an error (default: off)|
|verbosity||INT||logging verbosity level [0-5] (default: 0)|
|chunk_size||INT||data chunk size (B) (default: 4 MiB)|
|shmem_size||INT||maximum size (B) of data in shared memory (default: 256 MiB)|
|spill_size||INT||maximum size (B) of data in spillover file (default: 4 GiB)|
|spill_dir||STRING||path to spillover data directory|
|tcp||BOOL||Use TCP for server-to-server rpcs (default: on, turn off to enable libfabric RMA)|
|client_timeout||INT||timeout in milliseconds for rpcs between client and server (default: 5000)|
|server_timeout||INT||timeout in milliseconds for rpcs between servers (default: 15000)|
|dir||STRING||path to directory to contain server-local state|
|hostfile||STRING||path to server hostfile|
|init_timeout||INT||timeout in seconds to wait for servers to be ready for clients (default: 120)|
|local_extents||BOOL||use server extents to service local reads without consulting file owner|
|dir||STRING||path to directory to contain server shared files|
All environment variables take the form
UNIFYFS_SECTION_KEY, except for
[unifyfs] section, which uses
UNIFYFS_KEY. For example,
log.verbosity has a corresponding environment variable
unifyfs.mountpoint corresponds to
Command Line Options¶
For server command line options, we use
getopt_long() format. Thus, all
command line options have long and short forms. The long form uses
--section-key=value, while the short form
-<optchar> value, where
the short option character is given in the below table.
Note that for configuration options of type BOOL, the value is optional.
When not provided, the
true value is assumed. If the short form option
is used, the value must immediately follow the option character (e.g.,