zRAM broken on Raring?

Nio Wiklund nio.wiklund at gmail.com
Fri Sep 27 21:54:46 UTC 2013

On 2013-09-27 23:28, John Hupp wrote:
> On Raring, output from 'sudo parted -l' includes:
>     Error: /dev/zram0: unrecognised disk label
> And syslog shows a slew of errors:
>     Lubuntu kernel: Buffer I/O error on device zram0, logical block 128247
> Syslog also indicates that half of memory was given to zram to form its
> block device.
> Does this mean that half of memory is dedicated to something that isn't
> working?  And perhaps that machines will hang when swap is needed?
> I arrive at this line of questioning because I was testing an LTSP
> client using a Lubuntu LTSP server configured with 1 GB, and when I drop
> the client memory configuration to 256 MB, the *server* has hung on
> several occasions when I was starting or stopping Firefox on the client
> (though in one case this coincided with the startup of a SpiderOak
> backup operation).   I didn't think of the Magic SysRq keys at the time,
> and nothing else was responding, so I did hard shutdowns.
> I saw a post from Phill Whiteside recently concerning a rush of activity
> re a zram bug, but it seemed to be directed at Saucy.
> Are there solutions/workarounds?
You find a lot of details reading the comments about this bug.


There is a kernel in the pipeline, that we think will solve most if not
all of the problems. Until we get the kernel that can cooperate with
zRAM, you can switch it off either manually or with crontab like this:

guru at Lubuntu-Saucy-b2:~$ sudo crontab -l |tail -n3
# m h  dom mon dow   command
@reboot              /sbin/swapoff /dev/zram*
@reboot              /sbin/rmmod zram

Best regards

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