Provided by: systemd-zram-generator_0.3.2-1_amd64 bug

NAME

       zram-generator.conf - Systemd unit generator for zram swap devices (configuration)

SYNOPSIS

       /usr/lib/systemd/zram-generator.conf
       /usr/local/lib/systemd/zram-generator.conf
       /etc/systemd/zram-generator.conf
       /run/systemd/zram-generator.conf

       /usr/lib/systemd/zram-generator.conf.d/*.conf
       /usr/local/lib/systemd/zram-generator.conf.d/*.conf
       /etc/systemd/zram-generator.conf.d/*.conf
       /run/systemd/zram-generator.conf.d/*.conf

DESCRIPTION

       These  files  configure  devices created by zram-generator(8). See systemd.syntax(5) for a
       general description of the syntax.

CONFIGURATION DIRECTORIES AND PRECEDENCE

       The     default     configuration     doesn't     specify     any     devices.     Consult
       /usr/share/zram-generator/zram-generator.conf.example for an example configuration file.

       When packages need to customize the configuration, they can install configuration snippets
       in /usr/lib/systemd/zram-generator.conf.d/. Files in /etc/  are  reserved  for  the  local
       administrator,  who  may  use  this logic to override the configuration files installed by
       vendor packages. The main configuration file is  read  before  any  of  the  configuration
       directories,  and  has  the  lowest  precedence;  entries  in  a file in any configuration
       directory override entries in the  single  configuration  file.  Files  in  the  *.conf.d/
       configuration  subdirectories  are  sorted  by  their  filename  in  lexicographic  order,
       regardless of which of the subdirectories they reside in. When multiple files specify  the
       same  option, for options which accept just a single value, the entry in the file with the
       lexicographically latest name takes precedence. It is recommended to prefix all  filenames
       in  those  subdirectories  with a two-digit number and a dash, to simplify the ordering of
       the files.

       To disable a configuration file supplied by the vendor, the recommended way is to place  a
       symlink  to  /dev/null  in the configuration directory in /etc/, with the same filename as
       the vendor configuration file.

       The  generator  understands   the   following   option   on   the   kernel   command-line:
       systemd.zram[=0|1]. When specified with a true argument (or no argument), the zram0 device
       will be created. Default options apply, but may be overridden by configuration on disk  if
       present.  When  specified  with  a  false argument, no zram devices will be created by the
       generator. This option thus has higher priority than the configuration files.

OPTIONS

       Each device is configured independently in its [zramN] section, where N is  a  nonnegative
       integer. Other sections are ignored.

       Devices with the final size of 0 will be discarded.

       ○   host-memory-limit=

           Sets the upper limit on the total usable RAM (as defined by MemTotal in /proc/meminfo,
           confer proc(5)) above which the device will not be created.

           This takes a nonnegative number, representing that limit in megabytes, or the  literal
           string none, which can be used to override a limit set earlier.

           Defaults to none.

           For  compatibility with earlier versions, memory-limit is allowed as an alias for this
           option.   Its   use   is   discouraged,   and   administrators   should   migrate   to
           host-memory-limit.

       ○   zram-fraction=

           Defines the scaling factor of the zram device's size with relation to the total usable
           RAM.

           This takes a nonnegative floating-point number representing that factor.

           Defaults to 0.5.

       ○   max-zram-size=

           Sets the limit on the zram device's size obtained by zram-fraction.

           This takes a nonnegative number, representing that limit in megabytes, or the  literal
           string none, which can be used to override a limit set earlier.

           Defaults to 4096.

       ○   compression-algorithm=

           Specifies the algorithm used to compress the zram device.

           This takes a literal string, representing the algorithm to use.
           Consult  /sys/block/zram0/comp_algorithm  for  a  list of currently loaded compression
           algorithms, but note that additional ones may be loaded on demand.

           If unset, none will be configured and the kernel's default will be used.

       ○   swap-priority=

           Controls the relative swap priority, a value between  -1  and  32767.  Higher  numbers
           indicate higher priority.

           If unset, 100 is used.

       ○   mount-point=

           Format the device with a file system (not as swap) and mount this file system over the
           specified directory. When neither this option nor fs-type= is  specified,  the  device
           will be formatted as swap.

           Note  that the device is temporary: contents will be destroyed automatically after the
           file system is unmounted (to release the backing memory).

       ○   fs-type=

           Specifies how the device shall be formatted. The default is  ext2  if  mount-point  is
           specified,  and swap otherwise. (Effectively, the device will be formatted as swap, if
           neither fs-type= nor mount-point= are specified.)

           Note that the device is temporary: contents will be destroyed automatically after  the
           file system is unmounted (to release the backing memory).

           Also see systemd-makefs(8).

ENVIRONMENT VARIABLES

       Setting  ZRAM_GENERATOR_ROOT  during  parsing  will  cause  /proc/meminfo  to be read from
       $ZRAM_GENERATOR_ROOT/proc/meminfo                       instead,                       and
       {/usr/lib,/usr/local/lib,/etc,/run}/systemd/zram-generator.conf    to    be    read   from
       $ZRAM_GENERATOR_ROOT/{/usr/lib,/usr/local/lib,/etc,/run}/systemd/zram-generator.conf.

EXAMPLES

       The default configuration will yield the following:

            zram device size [MB]
                ^
                │
             4G>│               ooooooooooooo
                │             o
                │           o
                │         o
             2G>│       o
                │     o
                │   o
           512M>│ o
                0───────────────────────> total usable RAM [MB]
                  ^     ^       ^
                  1G    4G      8G

REPORTING BUGS

       <https://github.com/systemd/zram-generator/issues>

SEE ALSO

       zram-generator(8), systemd.syntax(5), proc(5)

       <https://github.com/systemd/zram-generator>

       Linux                     documentation                      of                      zram:
       <https://kernel.org/doc/html/latest/admin-guide/blockdev/zram.html>
       and                  the                  zram                  sysfs                 ABI:
       <https://kernel.org/doc/Documentation/ABI/testing/sysfs-block-zram>