NAME

       zram-generator - Systemd unit generator for zram swap devices

SYNOPSIS

       /usr/lib/systemd/system-generators/zram-generator TARGET_DIR [2RGET_DIR 3RGET_DIR]
       /usr/lib/systemd/system-generators/zram-generator --setup-device DEVICE
       /usr/lib/systemd/system-generators/zram-generator --reset-device DEVICE

DESCRIPTION

       zram-generator is a generator that creates systemd units to format and use compressed RAM devices, either
       as swap or a mount point.

       The generator will be invoked by systemd early at boot. The generator will then:

       1.  read configuration files from {/etc,/lib}/systemd/zram-generator.conf[.d] (see zram-generator.conf(5)
           for details);

       2.  generate   systemd.swap(5)  and/or  systemd.mount(5)  units  into  TARGET_DIR  and  connect  them  to
           swap.target or local-fs.target as appropriate;

       3.  ensure the zram module is loaded and create the requested devices.

       The  generator  does  nothing  if  run  inside  a  container  (as  determined  by  systemd-detect-virt(8)
       --container).

       The  generator  also  understands the kernel command-line option systemd.zram. See zram-generator.conf(5)
       for details.

       Setting the ZRAM_GENERATOR_ROOT environment variable makes the generator run in test mode, in which  case
       containerisation is ignored and step 3 is skipped.
       For the ramifications of ZRAM_GENERATOR_ROOT on config handling, see zram-generator.conf(5).

       Generated dev-zramN.swap units depend on systemd-swap-create@zramN.service, which will:

       1.  read configuration files from {/etc,/lib}/systemd/zram-generator.conf[.d] (see zram-generator.conf(5)
           for details);

       2.  set the desired compression algorithm, if any; if the current kernel doesn't understand the specified
           algorithm, a warning is issued, but execution continues;

       3.  set the desired blockdev size and format it as swap with systemd-makefs(8).

       Generated  path-to-mount-point.mount  units  depend  on  systemd-swap-create@zramN.service. The effect is
       similar to what happens for swap units, but of course they are formatted with a file system.

       When the unit is stopped, the zram device is reset, freeing memory and allowing the device to be reused.

       zram-generator implements systemd.generator(7).

REPORTING BUGS

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

SEE ALSO

       zram-generator.conf(5), systemd.generator(7), systemd.swap(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>

zram-generator developers                         October 2021                                 ZRAM-GENERATOR(8)