[Arm-dev] Using zram-swap

Robert Moskowitz rgm at htt-consult.com
Fri Oct 12 16:46:21 UTC 2018

It is now built into Fedora29-arm.  That is where Mark got the source 
and the systemd support.  Yes, earlier many just used it. Now Fedora-arm 
is based on it.

On the Fedora-arm list, Peter Robinson has said he is seeing 4-5 fold 
compression.  That means that if you use a factor of 2 and have a 1GB 
memory SOC, that is effectively 2.5GB ram.  Or use a factor of 4 for 
effectively 1.75GB and less 'swapping'.  So you can use your 1GB duo 
core system more effectively, even if you currently have swap on a HD or 
SSD sata or USB attached.

On 10/12/18 12:25 PM, Gordan Bobic wrote:
> Because swapping to SD card is slow, swapping to zram is fast, and 
> zram only takes about 1/2 of the RAM that it provides.
> It's basically RAM compression.
> It works and makes a positive difference, even without exceedingly 
> slow storage.
> On Fri, Oct 12, 2018 at 5:16 PM Fred Gleason <fredg at paravelsystems.com 
> <mailto:fredg at paravelsystems.com>> wrote:
>     On Oct 7, 2018, at 07:58, Robert Moskowitz <rgm at htt-consult.com
>     <mailto:rgm at htt-consult.com>> wrote:
>>     I have very recently learned about zram-swap. Fedora-29-arm is
>>     using it.  It supposedly makes a considerable difference even
>>     over HD swap.
>>     Since many (potential) users of Centos-arm do not have a ready
>>     HD, perhaps we can switch the image from a physical partition to
>>     zram? Or at least instructions to change to this on the wiki.
>     Not to be utterly naive, but why is swap required on such systems
>     at all? To take core RAM and repurpose it as swap would seem to
>     vitiate the entire point of having a virtual memory subsystem in
>     the first place.
>     Cheers!
>     |----------------------------------------------------------------------|
>     | Frederick F. Gleason, Jr. |              Chief Developer        
>         |
>     |                         |              Paravel Systems             |
>     |----------------------------------------------------------------------|
>     | Perfection is reached, not when there is no longer anything to
>     add,  |
>     | but when there is no longer anything to take away.               |
>     |                                   -- Antoine de Saint-Exupery  
>         |
>     |----------------------------------------------------------------------|
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