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Re: How to use zram ?




On יום חמישי, 28 בספטמבר 2017 12:27:01 IDT Pierre Couderc wrote:
> On 09/28/2017 11:56 AM, tomas@xxxxxxxxxx wrote:
> > On Thu, Sep 28, 2017 at 11:47:56AM +0200, Pierre Couderc wrote:
> >> I have found no howto for zram under debian,  nor even the word
> >> "zram" in the archives of this list !
> >> 
> >> I have tried to use zramctl but it refuses with :
> >> 
> >> root@nous:~# zramctl --find --size 1024M
> >> zramctl: no free zram device found
> >> 
> >> I suppose I should init something somewere, but what ?
> >> 
> >> On the contrary ubuntu has a dedicated zram-config to make the job.
> >> 
> >> Thanks for any help.
> > 
> > I didn't even know what it is -- but the zram(8) man page and a little
> > guesswork at least leads in some direction.
> > 
> > I assume you'd want to load the zram kernel module (sudo modprobe zram,
> > I'd guess) to be in in the fun.
> > 
> > There's some doc about the Linux kernel module itself (just follow the
> > link in the above man page).
> > 
> > Let us know how it works out and... make a backup first!
> 
> Thank you very much. I have not found "the zram(8) man page "... But It
> seems to work :
> 
> root@nous:~# modprobe zram num_devices=2
> root@nous:~# zramctl --find --size 1024M
> /dev/zram0
> root@nous:~# zramctl --find --size 1024M
> /dev/zram1
> root@nous:~# free -th
>                total        used        free      shared buff/cache  
> available
> Mem:           3.8G         73M        3.6G        5.5M 146M        3.5G
> Swap:            0B          0B          0B
> Total:         3.8G         73M        3.6G
> root@nous:~# mkswap /dev/zram0
> Setting up swapspace version 1, size = 1024 MiB (1073737728 bytes)
> no label, UUID=66e3aa01-a4b8-4308-b317-608c6a072810
> root@nous:~# free -th
>                total        used        free      shared buff/cache  
> available
> Mem:           3.8G         73M        3.6G        5.5M 146M        3.5G
> Swap:            0B          0B          0B
> Total:         3.8G         73M        3.6G
> root@nous:~# swapon /dev/zram0
> root@nous:~# free -th
>                total        used        free      shared buff/cache  
> available
> Mem:           3.8G         73M        3.6G        5.5M 147M        3.5G
> Swap:          1.0G          0B        1.0G
> Total:         4.8G         73M        4.6G
> root@nous:~# mkswap /dev/zram1
> Setting up swapspace version 1, size = 1024 MiB (1073737728 bytes)
> no label, UUID=69b8070b-3b8d-4234-a773-a59812e54552
> root@nous:~# swapon /dev/zram1
> root@nous:~# free -th
>                total        used        free      shared buff/cache  
> available
> Mem:           3.8G         74M        3.6G        5.5M 147M        3.5G
> Swap:          2.0G          0B        2.0G
> Total:         5.8G         74M        5.6G
> root@nous:~#
> 
> Now I suppose I shouls put that in a systemd script...
> 
> Thank you very much.
> 
> PC

Did all this.
All my free -th results looked the same.
Could it be it was already there?

Assuming there is an advantage to this, how does one get it going on startup. 
I HAD a sysinit script for it at one time, before the new days of systend.