Customize alternate install CD with UEFI?

Liam Proven lproven at gmail.com
Fri Jul 22 15:36:19 UTC 2016


On 22 July 2016 at 17:23, Colin Law <clanlaw at gmail.com> wrote:
> I don't think that is quite true, I believe swapspace will
> automatically adjust the size of the swapfile.  I did have some
> problems with swapspace (around Ubuntu 15.04 I think, maybe earlier)
> where it started consuming 100% of the processor.  I think it may have
> been to do with suspend/resume if I remember correctly.  I switched to
> using a regular fixed size swapfile and have had no problems since.
> As Josef said it appears swapspace is no longer supported [0]
>
> Colin
>
> [0] http://pqxx.org/development/swapspace/

It's ripe for someone to take it over and update it as needed then!

One caveat is that since Linux hibernation support stores the memory
image in the swap partition, you must have a dedicated swap partition
for it to work. It needs to be big enough to store all the _used_
memory.

As far as I can tell, the unified disk (etc.) cache is flushed before
hibernation, so this does not need to be stored. It is often the
majority of memory contents on a lightly to moderately loaded machine.

To my surprise, on one of my machines, after I upgraded the RAM from
4GB to 8GB, the machine was still able to successfully hibernate and
wake again with only a 4GB swap partition. However, if RAM is
overcommitted and the machine is already swapping, then you will need
more swap than RAM. Given that disk space is very cheap and plentiful
these days, then the old formula of (swap = 2 x RAM) seems to work
still.

In my experiments, hibernation is incompatible with both ZRAM and
swapspace. You need a dedicated swap partition and _only_ a partition.

I am not sure if the Linux memory manager's "swappiness" parameter...

http://askubuntu.com/questions/103915/how-do-i-configure-swappiness

... can be individually tuned for multiple different forms of swap.
Thus, I don't think it's a good idea to combine different swap media
-- I use /either/ ZRAM /or/ swapfiles /or/ a swap partition, not 2 or
more of them.

In theory, it would be useful to combine 2 of them, perhaps, but I
don't think there is any way to tell the kernel "swap preferentially
to ZRAM until RAM usage is over 75% then use the file/partition".


-- 
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