Re: fstab zram swap integration idea

[Karel Zak <kzak@redhat.com>]

On Mon, Jan 07, 2013 at 05:52:28PM +0300, Maksim Melnikau wrote:
> On Mon, Jan 7, 2013 at 3:42 PM, Karel Zak <kzak@redhat.com> wrote:
> >  Is it designed for anything other than swaparea?
> Yes, zram is kind-of "compressed" block device in memory, any block
> device operations could be done on top of it. Some people initialize
> ext4 partitions "in memory" for temporary operations.
> So, I still think fstab is correct place for describing fs/swap even
> for zram. Questions are: 1) what is correct place for mkfs/mkswap zram
> devices, at startup? 2) What is correct place for setting size for
> zram block device? (right now I use systemd's tmpfiles.d)

I see two independent operations

  1/ initialize zram device
  2/ create on-device filesystem/swap

in our previous emails we have talked about 2/ for swap (call mkswap).

I'm not sure if 1/ belongs to swapon/mount. It seems better to create
a special udev rule for this purpose (we use the same solution for
example for raw devices) or systemd unit.

Note that the ideal solution is to have a special daemon for block
devices management where you can configure complex scenarios and ask
for usable device/filesystem.... but something like this is not
implemented yet. These things are too complicated to hide it into
mount/swapon.

    Karel


-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com