Best way to use zram in Fedora 21?

Corey Sheldon sheldon.corey at
Fri Nov 28 03:40:16 UTC 2014

ok to the naming and multi zram devices questions:

1) one single large space is wasteful if you have your machine up for
longer than a  single (or series ) of heavy lifting operations  --say you
are rendering a video and then back to the usual grind stuff would you want
all that extra space just wasted ?  also say a follow up process is in need
of more would you wanna be stuck on previous values?   zram is dynamic in
nature smaller more numerous /dev/zram$i  allows for that and in a dynamic

2) it the RAM its based off not swap and the "z" is known as dynamic

Corey W Sheldon
Freelance IT Consultant, Multi-Discipline Tutor

On Thu, Nov 27, 2014 at 7:39 PM, Reindl Harald <h.reindl at>

> Am 28.11.2014 um 01:34 schrieb Zbigniew Jędrzejewski-Szmek:
>> On Fri, Nov 28, 2014 at 01:21:26AM +0100, Zbigniew Jędrzejewski-Szmek
>> wrote:
>>> On Thu, Nov 27, 2014 at 04:42:36PM +0100, Juan Orti wrote:
>>>> El 2014-11-27 14:48, Reindl Harald escribió:
>>>>> Am 27.11.2014 um 14:25 schrieb Juan Orti:
>>>>>> Reindl, I'm of the opinion you should upload your scripts to some git
>>>>>> repository and package them to be part of the distribution. I can
>>>>>> co-maintain if you wish
>>>>> feel free to package it!
>>>>> that's why i attached it as i saw the topic
>>>>> i am not a active packager on the Fedora infrastrcuture
>>>> Ok, I've uploaded the scripts to GitHub and submitted a review request:
>>> I have a question about the code: why are multiple swap devices needed?
>>> /sys/block/zram0/max_comp_streams can be set to whatever number is
>>> wanted. While it might be useful to have additional zram devices
>>> for different purposes, I don't think more than one zram swap is
>>> useful. If you only have one device, then reloading the module is
>>> no longer necessary to change the parameters, since everything
>>> else seems to be configurable through sysfs.
>> And another question (sorry, I never used compressed swap before):
>> why not zswap? It seems to be a better fit for the desktop/server
>> environments that Fedora is used for. IIUC, zswap is better because
>> it overflows automatically into the backing swap device
> on machines with plenty RAM i prefer not have a swap partition or a swap
> file at all - especially on virtual machines it's a waste of (possible
> expensive SAN) disk storage
> on virtual servers currently i prefer zram inside the guest to avoid OOM
> conditions in the guest while the memory compression of the hypervisor
> steps in too late and is more for overcommit the host
> --
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