/dev/zram0 - How to Remove It?

[mapes12]

Running Ubu 12.04 LTS. My machine has been behaving oddly just lately. On furth investigation I've discovered that there is a swap file in memory known as /dev/zram0. I've Googled for a removal solution but found nothing that describes the uninstallation in simple English. It appears that Casper may have something to do with why this /dev/zram0 has been created. Also, I've been connecting a FLIP video recorder to the machine periodically to move some video clips ontp my HDD. Some have suggested that this may have been part of the problem as well.

I've attached a scrrenshot.

Can anyone tell me how to get rid of this please?

Mark

[Paqman]

Generally you don't touch anything in /dev, these are the kernel's way of representing hardware (everythin in Linux is a file, even devices).

Have you been able to pin down exactly when this pops up? Zram is a RAM compression system. Is it there right after you boot? Or does it only pop up after you plug your Flip in?

[mapes12]

Have you been able to pin down exactly when this pops up? Zram is a RAM compression system. Is it there right after you boot? Or does it only pop up after you plug your Flip in?I have no peripheral devices attached and the /dev/zram0 remains as previously stated. Even when I reboot it stays there. I'm not sure if it's related but I also have a /proc file being reported at 140.7TB. The HDD is only 250GB. Screenshot attached. This came to light the other day when I tried to backup my system with Remastersys. Clearly, Remastersys fell over when it found that file.

[dannyboy79]

your first picture clearly shows it under the USB, Firewire, periphial device. Not sure what's going on IF you don't have anything plugged in. Maybe it didn't unmount properly. You say you rebooted?

Proc is always going to be there and I'd leave it alone but I am not sure why it's stating it's TB in size when your HDD is only 250GB

you could try

swapoff /dev/zram0

[grahammechanical]

Now here is a strange thing. When I look at the properties of the proc folder for the Ubuntu install that I am at present using it says:

56,393 items, totaling 140.7TB. I guess that 'proc' = processess. Perhaps 140.7TB is a theoretical limit to the size of the file system that Linux processes can run in and the processes are not limited except by that theoretical limit.

I found this.


/proc is very special in that it is also a virtual filesystem. It's sometimes referred to as a process information pseudo-file system. It doesn't contain 'real' files but runtime system information


The most distinctive thing about files in this directory is the fact that all of them have a file size of 0, with the exception of kcore, mtrr and self. A directory listing looks similar to the following:

http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/proc.html

And this


Like all other files below /proc the kcore file is only a virtual file. It contains the RAM the kernel can allocate. Therefore this should not be touched or read. It is nothing to worry about. This file doesn't use actual disk space and only exists virtually.

Note: On 64-bit systems the size of /proc/kcore is even 128TB because that's the absolute limit of what 64-bit systems can allocate.

http://www.novell.com/support/kb/doc.php?id=7004153

There are ways of counting bytes that would make 128TB = 140.7TB.

Regards.

[Paqman]

Definitely do not go poking around in /proc, there's nothing user-editable in there. Just think of it as a big dark hole full of weird kernel stuff.

[mapes12]

swapoff /dev/zram0Thanks Dannyboy79. I ran that code but the /dev/zram0 is still there per my first post.

Grahammechanical - I've booted from a live CD. The live CD session /proc file appears empty but the HDD /proc file is still there at 140.7TB so I have no idea what's going on there?

[MG&TL]

Definitely do not go poking around in /proc, there's nothing user-editable in there. Just think of it as a big dark hole full of weird kernel stuff.

Well...don't go editing anything in there. Some of the files are quite interesting. ;)

[tgalati4]

Post the output of:


free

Do you not have a real, hard disk swap partition? If not, then create one and it will get mounted and possibly not use /dev/zram0.

[mapes12]

free

mark@mark-ubu-laptop:~$ free
total used free shared buffers cached
Mem: 3043884 1333624 1710260 0 113368 573936
-/+ buffers/cache: 646320 2397564
Swap: 5427472 0 5427472


Do you not have a real, hard disk swap partition? If not, then create one and it will get mounted and possibly not use /dev/zram0.Yes, It's always had a swap partition:-


mark@mark-ubu-laptop:~$ sudo fdisk -l
[sudo] password for mark:

Disk /dev/sda: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000c2e85

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 172859391 86428672 83 Linux
/dev/sda2 172861438 488396799 157767681 5 Extended
/dev/sda5 480585728 488396799 3905536 82 Linux swap / Solaris
/dev/sda6 172861440 480583679 153861120 83 Linux

Partition table entries are not in disk order

[mapes12]

Here's fdisk -l in the GUI.

[Cheesemill]

It looks like the zram kernel module is being loaded. What is the output of...

lsmod | grep zram
zramconfig /dev/zram0 --stats

[mapes12]

Looks like the second command didn't do anything.


mark@mark-ubu-laptop:~$ lsmod | grep zram
zram 18642 1



mark@mark-ubu-laptop:~$ zramconfig /dev/zram0 --stats
zramconfig: command not found

[Cheesemill]

You could try installing zramconfig and then using it to turn off the feature.


sudo apt-get update
sudo apt-get install zramconfig
sudo swapoff /dev/zram0
sudo umount /dev/zram0
sudo zramconfig /dev/zram0 --reset

[mapes12]

Update went fine then I got:-


mark@mark-ubu-laptop:~$ sudo apt-get install zramconfig
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package zramconfigWhich repo is it in?

[Cheesemill]

Sorry, that should be zram-config.

[mapes12]

mark@mark-ubu-laptop:~$ sudo apt-get install zram-config
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed
zram-config
0 upgraded, 1 newly installed, 0 to remove and 8 not upgraded.
Need to get 3,078 B of archives.
After this operation, 42.0 kB of additional disk space will be used.
Get:1 http://gb.archive.ubuntu.com/ubuntu/ precise/universe zram-config all 0.1 [3,078 B]
Fetched 3,078 B in 0s (23.8 kB/s)
Selecting previously unselected package zram-config.
(Reading database ... 228552 files and directories currently installed.)
Unpacking zram-config (from .../zram-config_0.1_all.deb) ...
Processing triggers for ureadahead ...
ureadahead will be reprofiled on next reboot
Setting up zram-config (0.1) ...
start: Job failed to start
invoke-rc.d: initscript zram-config, action "start" failed.
dpkg: error processing zram-config (--configure):
subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
zram-config
E: Sub-process /usr/bin/dpkg returned an error code (1)Then Apport kicked in and fired off an error report.

The above installation error is a known Bug Report in Launchpad and is under investigation. Can't see that there is much more I can do now.

[tgalati4]

How did /dev/zram0 get installed in the first place? Is it part of a Virtual Machine installation?

[mapes12]

How did /dev/zram0 get installed in the first place? Is it part of a Virtual Machine installation?I've had Parallels Workstation and Parallels Transporter installed on this machine for ages but never set up a OS within them. As far as I can recall zram has only just started to appear on my system. I'm thinking that perhaps a Kernel upgrade that came through the other week as part of the regular Updates may have had something in it that detected the VM installation capability and initiated the zram configuaration at boot up. I'm guessing here.The plot thickens. If you look at my earlier screenshots you will see zram0 at 1.6GB. It's now morphed itself into zram0 and zram1 both at 779MB each. See attached updated screenshot.

[tgalati4]

I did a fresh install of 12.10 on my laptop without any VM's and I don't have a zram0. So I think you are correct, it's associated with Parallels. Perhaps there is a Parallels removal tool if you are not using it?

[mapes12]

I did a fresh install of 12.10 on my laptop without any VM's and I don't have a zram0. So I think you are correct, it's associated with Parallels. Perhaps there is a Parallels removal tool if you are not using it?I've come to the same conclusion. I'll have a go at uninstalling Parallels today and see what happens.

After going through this process I've discovered that zram looks like a good thing so I'm not overly concerned about it running anymore. I like to make good state backups of my system using Remasterys but at the moment Remastersys falls over and reports that it's run into a file that's taking it over the 4GB limit. I keep all my data on a separate partition and only have the / files on my first boot partition so I know it's not data overload. That /proc file appears to be the issue which is perhaps a subject for another thread. I'll post again once I've had a go at removing Parallels.

[mapes12]

Booted up my machine this morning to discover that zram has not loaded. I have made no configuration changes and not run any applications that weren't running the last time I posted screenshots. Most stange :???:

[sengerandu]

Did you do any uninstallation or it automatically disappeared? I am also interested to know what causes the kernel to create such an entry?

[vueja]

The zram0 automatic appear too when install unetbootin and then restart. :KS

[Cvetan]

I had the same problem with zram0. I also got zram1, 2 and 3 when i installed zram-config.

Had some problems with it also, so i removed the package. Suprisingly all the zrams were gone. :)

[Cvetan]

No it was only until reboot. Zram0 is back :(

[heir4c]

Take a look here:
http://askubuntu.com/questions/174579/how-do-i-use-zram