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Groups > linux.debian.user > #187350 > unrolled thread

How to use zram ?

Started byPierre Couderc <pierre@couderc.eu>
First post2017-09-28 11:50 +0200
Last post2017-09-28 17:00 +0200
Articles 19 — 8 participants

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Contents

  How to use zram ? Pierre Couderc <pierre@couderc.eu> - 2017-09-28 11:50 +0200
    Re: How to use zram ? <tomas@tuxteam.de> - 2017-09-28 12:00 +0200
      Re: How to use zram ? Pierre Couderc <pierre@couderc.eu> - 2017-09-28 12:30 +0200
        Re: How to use zram ? <tomas@tuxteam.de> - 2017-09-28 14:10 +0200
        Re: How to use zram ? David Baron <dbaron770@gmail.com> - 2017-09-28 14:20 +0200
          Re: How to use zram ? Pierre Couderc <pierre@couderc.eu> - 2017-09-28 16:50 +0200
        Re: How to use zram ? Richard Owlett <rowlett@cloud85.net> - 2017-09-28 17:00 +0200
    Re: How to use zram ? <tomas@tuxteam.de> - 2017-09-28 16:00 +0200
      Re: How to use zram ? Gene Heskett <gheskett@shentel.net> - 2017-09-28 16:20 +0200
        Re: How to use zram ? <tomas@tuxteam.de> - 2017-09-28 16:40 +0200
          Re: How to use zram ? Gene Heskett <gheskett@shentel.net> - 2017-09-28 17:50 +0200
            Re: How to use zram ? Greg Wooledge <wooledg@eeg.ccf.org> - 2017-09-28 17:50 +0200
          Re: How to use zram ? Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-09-28 18:10 +0200
            Re: How to use zram ? <tomas@tuxteam.de> - 2017-09-28 19:20 +0200
        Re: How to use zram ? Pierre Couderc <pierre@couderc.eu> - 2017-09-28 17:00 +0200
          Re: How to use zram ? Nicholas Geovanis <nickgeovanis@gmail.com> - 2017-09-28 17:20 +0200
      Re: How to use zram ? Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-09-28 18:00 +0200
    Re: How to use zram ? Gene Heskett <gheskett@shentel.net> - 2017-09-28 16:00 +0200
      Re: How to use zram ? Pierre Couderc <pierre@couderc.eu> - 2017-09-28 17:00 +0200

#187350 — How to use zram ?

FromPierre Couderc <pierre@couderc.eu>
Date2017-09-28 11:50 +0200
SubjectHow to use zram ?
Message-ID<uuDCa-7kq-15@gated-at.bofh.it>
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.

PC

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#187351

From<tomas@tuxteam.de>
Date2017-09-28 12:00 +0200
Message-ID<uuDLR-7o2-47@gated-at.bofh.it>
In reply to#187350
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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!

Cheers
- -- tomás
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#187352

FromPierre Couderc <pierre@couderc.eu>
Date2017-09-28 12:30 +0200
Message-ID<uuEeS-7MF-11@gated-at.bofh.it>
In reply to#187351
On 09/28/2017 11:56 AM, tomas@tuxteam.de 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

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#187355

From<tomas@tuxteam.de>
Date2017-09-28 14:10 +0200
Message-ID<uuFND-nv-11@gated-at.bofh.it>
In reply to#187352
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On Thu, Sep 28, 2017 at 12:27:01PM +0200, Pierre Couderc wrote:
> On 09/28/2017 11:56 AM, tomas@tuxteam.de wrote:

[...]

> >I didn't even know what it is -- but the zram(8) man page and a little
> >guesswork at least leads in some direction.

> Thank you very much. I have not found "the zram(8) man page "... But
> It seems to work :

Bah. I wanted to write  zramctl(8). How embarrasing :-)

But hey, glad it worked!

[...]

> Thank you very much.

Thank you for your detailed report.

Cheers
- -- tomás
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#187356

FromDavid Baron <dbaron770@gmail.com>
Date2017-09-28 14:20 +0200
Message-ID<uuFXk-sz-11@gated-at.bofh.it>
In reply to#187352
On יום חמישי, 28 בספטמבר 2017 12:27:01 IDT Pierre Couderc wrote:
> On 09/28/2017 11:56 AM, tomas@tuxteam.de 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.

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#187368

FromPierre Couderc <pierre@couderc.eu>
Date2017-09-28 16:50 +0200
Message-ID<uuIit-1KL-1@gated-at.bofh.it>
In reply to#187356

[Multipart message — attachments visible in raw view] — view raw

On 09/28/2017 02:11 PM, David Baron wrote:
>>
>> ... 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.
>
I have decided to use the following script and it seems to work :

git  clone https://github.com/Jiab77/systemd-zram
cd systemd-zram
./install.sh

You can the remove systemd-zram directory.

Here you can modify /etc/systemd/zram.conf from 33% to 50 for next 
reboot… But it is only to adopt the same policy as Ubuntu,  but the 
original prefers 33%...

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#187370

FromRichard Owlett <rowlett@cloud85.net>
Date2017-09-28 17:00 +0200
Message-ID<uuIsa-1Of-13@gated-at.bofh.it>
In reply to#187352
On 09/28/2017 05:27 AM, Pierre Couderc wrote:
> [snip]
> Thank you very much. I have not found "the zram(8) man page
> [snip]

See https://manpages.debian.org/stretch/util-linux/zramctl.8.en.html

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#187359

From<tomas@tuxteam.de>
Date2017-09-28 16:00 +0200
Message-ID<uuHw5-1ff-9@gated-at.bofh.it>
In reply to#187350
-----BEGIN PGP SIGNED MESSAGE-----
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On Thu, Sep 28, 2017 at 09:51:21AM -0400, Gene Heskett wrote:
> On Thursday 28 September 2017 05:47:56 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 :
> >
> A better question from me might be, what is it?

It seems to be a way to swap out to "compressed RAM"[1] (sloppy, I know,
but you hopefully get the idea).

Cheers
[1] https://en.wikipedia.org/wiki/Zram

- -- tomás
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#187362

FromGene Heskett <gheskett@shentel.net>
Date2017-09-28 16:20 +0200
Message-ID<uuHPt-1Bi-21@gated-at.bofh.it>
In reply to#187359
On Thursday 28 September 2017 09:58:39 tomas@tuxteam.de wrote:

> On Thu, Sep 28, 2017 at 09:51:21AM -0400, Gene Heskett wrote:
> > On Thursday 28 September 2017 05:47:56 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 :
> >
> > A better question from me might be, what is it?
>
> It seems to be a way to swap out to "compressed RAM"[1] (sloppy, I
> know, but you hopefully get the idea).
>
I do have the kernel module, but not the zramctl. One is not useful w/o 
the other. But I learned something from this thread. Thanks.

> Cheers
> [1] https://en.wikipedia.org/wiki/Zram
>
> -- tomás


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#187367

From<tomas@tuxteam.de>
Date2017-09-28 16:40 +0200
Message-ID<uuI8P-1Hr-37@gated-at.bofh.it>
In reply to#187362
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Thu, Sep 28, 2017 at 10:09:27AM -0400, Gene Heskett wrote:
> On Thursday 28 September 2017 09:58:39 tomas@tuxteam.de wrote:

[...]

> I do have the kernel module, but not the zramctl. One is not useful w/o 
> the other. But I learned something from this thread. Thanks.

  tomas@rasputin:~$ apt-file search zramctl
  manpages-de: /usr/share/man/de/man8/zramctl.8.gz
  util-linux: /sbin/zramctl
  util-linux: /usr/share/bash-completion/completions/zramctl
  util-linux: /usr/share/man/man8/zramctl.8.gz

Remember Stacker? (this one is actually smarter, because when it *has* to
swap, the already compressed stuff gets swapped out, reducing I/O).

Cheers
- -- t
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#187376

FromGene Heskett <gheskett@shentel.net>
Date2017-09-28 17:50 +0200
Message-ID<uuJey-2kP-7@gated-at.bofh.it>
In reply to#187367
On Thursday 28 September 2017 10:37:19 tomas@tuxteam.de wrote:

> On Thu, Sep 28, 2017 at 10:09:27AM -0400, Gene Heskett wrote:
> > On Thursday 28 September 2017 09:58:39 tomas@tuxteam.de wrote:
>
> [...]
>
> > I do have the kernel module, but not the zramctl. One is not useful
> > w/o the other. But I learned something from this thread. Thanks.
>
>   tomas@rasputin:~$ apt-file search zramctl
>   manpages-de: /usr/share/man/de/man8/zramctl.8.gz
>   util-linux: /sbin/zramctl
Not in the x86 wheezy's util-linux, nor as separate package.
>   util-linux: /usr/share/bash-completion/completions/zramctl
>   util-linux: /usr/share/man/man8/zramctl.8.gz
>
> Remember Stacker? (this one is actually smarter, because when it *has*
> to swap, the already compressed stuff gets swapped out, reducing I/O).
>
Yes, not fondly though, it was NOT a stable utility.

This sounds handy on a memory starved machine. And at 8GB in this 
machine, I'm still using swap, with a 13 hour uptime, 22megs almost as 
soon as I'd rebooted, and still 22. Which I don't fully grok, htop says 
22 megs used for swap, and only about 60% of that 8GB in use. 2258M for 
actual programs. Linux's memory management does not impress me, I have a 
couple machines with only 2GB of ram that can do what this box is doing, 
albeit slower because they are, and I really have to push then hard to 
make them use any swap. Only the pi-3b with only 1 GB is into swap, but 
I've moved its swap out of the sd to rotating media and its much better 
behaved, and feels faster at 5 megs into swap than it ever was using the 
32GB sd card for swap. Well worth the $50 for a 1/4" thick seagate 
terrabyte with a usb-2 cable sticking out of it.

Now wallies has it with a usb-3 cable, I've put one on the rock64, and 
with 2+ days uptime it hasn't touched its 8GB of rotating swap. But its 
also not yet running x, having locale problems that apt and dpkg can't 
fix.

root@rock64:~# dpkg-reconfigure locale
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or 
directory
locale: Cannot set LC_ALL to default locale: No such file or directory
dpkg-query: package 'locale' is not installed and no information is 
available
Use dpkg --info (= dpkg-deb --info) to examine archive files,
and dpkg --contents (= dpkg-deb --contents) to list their contents.
/usr/sbin/dpkg-reconfigure: locale is not installed
root@rock64:~# apt install locale
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package locale

And there is indeed, no /etc/locale file on the rock64 install.  
locale.alias, which is missing any mention of en_US.  Puzzling.

> Cheers
> -- t

Thanks Thomas

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#187377

FromGreg Wooledge <wooledg@eeg.ccf.org>
Date2017-09-28 17:50 +0200
Message-ID<uuJez-2kP-41@gated-at.bofh.it>
In reply to#187376
On Thu, Sep 28, 2017 at 11:42:47AM -0400, Gene Heskett wrote:
> This sounds handy on a memory starved machine. And at 8GB in this 
> machine, I'm still using swap, with a 13 hour uptime, 22megs almost as 
> soon as I'd rebooted, and still 22. Which I don't fully grok, htop says 
> 22 megs used for swap, and only about 60% of that 8GB in use.

Freeing up the memory used by idle daemons and other layabouts lets the
system devote more memory to disk caching.

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#187379

FromPascal Hambourg <pascal@plouf.fr.eu.org>
Date2017-09-28 18:10 +0200
Message-ID<uuJxU-2Gx-21@gated-at.bofh.it>
In reply to#187367
Le 28/09/2017 à 16:37, tomas@tuxteam.de a écrit :
> 
> Remember Stacker?

The disk compression tool for MS-DOS ?

> (this one is actually smarter, because when it *has* to
> swap, the already compressed stuff gets swapped out, reducing I/O).

 From what I have read about zram, I did not get the impression that its 
contents can be swapped out to disk.

Aren't you confusing with zswap (compressed cache associated to a 
regular swap device) ?
<https://en.wikipedia.org/wiki/Zswap>

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#187382

From<tomas@tuxteam.de>
Date2017-09-28 19:20 +0200
Message-ID<uuKDE-3l8-21@gated-at.bofh.it>
In reply to#187379
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Hash: SHA1

On Thu, Sep 28, 2017 at 06:01:10PM +0200, Pascal Hambourg wrote:
> Le 28/09/2017 à 16:37, tomas@tuxteam.de a écrit :
> >
> >Remember Stacker?
> 
> The disk compression tool for MS-DOS ?
> 
> >(this one is actually smarter, because when it *has* to
> >swap, the already compressed stuff gets swapped out, reducing I/O).
> 
> From what I have read about zram, I did not get the impression that
> its contents can be swapped out to disk.
> 
> Aren't you confusing with zswap (compressed cache associated to a
> regular swap device) ?
> <https://en.wikipedia.org/wiki/Zswap>

Perhaps.

Cheers
- -- t
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#187369

FromPierre Couderc <pierre@couderc.eu>
Date2017-09-28 17:00 +0200
Message-ID<uuIsa-1Of-5@gated-at.bofh.it>
In reply to#187362
On 09/28/2017 04:09 PM, Gene Heskett wrote:
> On Thursday 28 September 2017 09:58:39 tomas@tuxteam.de wrote:
>
>> On Thu, Sep 28, 2017 at 09:51:21AM -0400, Gene Heskett wrote:
>>> On Thursday 28 September 2017 05:47:56 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 :
>>> A better question from me might be, what is it?
>> It seems to be a way to swap out to "compressed RAM"[1] (sloppy, I
>> know, but you hopefully get the idea).
>>
> I do have the kernel module, but not the zramctl. One is not useful w/o
> the other. But I learned something from this thread. Thanks.
>
zramctl is delivered in basic stretch (ot I did install it witohut 
knowing...) but see my other post for its use.

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#187372

FromNicholas Geovanis <nickgeovanis@gmail.com>
Date2017-09-28 17:20 +0200
Message-ID<uuILw-2bi-27@gated-at.bofh.it>
In reply to#187369

[Multipart message — attachments visible in raw view] — view raw

I'm trying to wrap my head around what the performance implications (or
advantages) of zram might be in the virtualized environments. Currently for
me that means mostly VMware and a little Xen. There are at least two
aspects, namely its potential use in the hypervisor and use in the VMs.
Does anyone have any guidance on this issue?
Second question: Do we know how the AWS-branded linux AMIs make use of zram
if at all?
Thanks.......Nick G

On Thu, Sep 28, 2017 at 9:54 AM, Pierre Couderc <pierre@couderc.eu> wrote:

>
> On 09/28/2017 04:09 PM, Gene Heskett wrote:
>
>> On Thursday 28 September 2017 09:58:39 tomas@tuxteam.de wrote:
>>
>> On Thu, Sep 28, 2017 at 09:51:21AM -0400, Gene Heskett wrote:
>>>
>>>> On Thursday 28 September 2017 05:47:56 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 :
>>>>>
>>>> A better question from me might be, what is it?
>>>>
>>> It seems to be a way to swap out to "compressed RAM"[1] (sloppy, I
>>> know, but you hopefully get the idea).
>>>
>>> I do have the kernel module, but not the zramctl. One is not useful w/o
>> the other. But I learned something from this thread. Thanks.
>>
>> zramctl is delivered in basic stretch (ot I did install it witohut
> knowing...) but see my other post for its use.
>
>
>

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#187378

FromPascal Hambourg <pascal@plouf.fr.eu.org>
Date2017-09-28 18:00 +0200
Message-ID<uuJoe-2om-19@gated-at.bofh.it>
In reply to#187359
Le 28/09/2017 à 15:58, tomas@tuxteam.de a écrit :
> 
> It seems to be a way to swap out to "compressed RAM"
Actually zram is just a compressed ramdisk block device.
It can be used as swap space or anything else.

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#187360

FromGene Heskett <gheskett@shentel.net>
Date2017-09-28 16:00 +0200
Message-ID<uuHw5-1ff-11@gated-at.bofh.it>
In reply to#187350
On Thursday 28 September 2017 05:47:56 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 :
>
A better question from me might be, what is it?

> 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.

No *buntu machines left here since lcnc switched to wheezy.

> Thanks for any help.
>
> PC


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#187371

FromPierre Couderc <pierre@couderc.eu>
Date2017-09-28 17:00 +0200
Message-ID<uuIsa-1Of-15@gated-at.bofh.it>
In reply to#187360

On 09/28/2017 03:51 PM, Gene Heskett wrote:
> On Thursday 28 September 2017 05:47:56 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 :
>>
> A better question from me might be, what is it?
>
>
https://en.wikipedia.org/wiki/Zram

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