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>