zRAM broken on Raring?
Nio Wiklund
nio.wiklund at gmail.com
Sat Sep 28 16:47:19 UTC 2013
+1 :-D
On 2013-09-28 18:27, Phill Whiteside wrote:
> Hi John,
>
> just to add to the fun, unit193 found
> this.... https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1215379
> So, I don't know if we should be using zram or zswap now! It needs
> looking into by someone with more skilled than me (shouldn't be too hard
> to find one of those!). Joe from the kernel team simply said that is for
> the flavours to decide what they use, they just make the kernel :D I've
> asked Julien to have a look into the matter. The chase that zram was
> experiencing in the 3.11 kernels has a fix, the other issues are
> separate bugs and it seems like they have been around for several
> cycles. It's amazing what skeletons come out of the cupboard when
> someone rattles it hard!
>
> Regards,
>
> Phill.
>
>
> On 28 September 2013 17:10, John Hupp <lubuntu at prpcompany.com
> <mailto:lubuntu at prpcompany.com>> wrote:
>
> Hi, Nio.
>
> That is what puzzled me about Phill's statement that before Saucy,
> zram "was there just not used."
>
> Your confirmation that it is not used in your up-to-date Raring
> install sent me looking for a package that depends on zram-config.
> I did a Dependencies search in Synaptic and found out that my
> installed ltsp-client package Recommends zram-config.
>
> The nicest solution scenarios would be that zram is fixed in time
> for the Saucy release (there is hope?) and that it is almost
> simultaneously backported to Raring (there is hope?).
>
> But in the meantime I suppose I'll need to talk to the LTSP folks
> about what might be done if neither of the above happens quickly.
>
> --John
>
> On 9/28/2013 4:04 AM, Nio Wiklund wrote:
>
> Hi John,
>
> I checked in an up to date (update + dist-upgrade) Lubuntu
> Raring i386
> standard desktop installation. I find no zRAM block devices, no
> zram-config, and nothing else, that indicates that zram should be
> activated. The kernel is 3.8.0.31 #46 according to uname.
>
> guru at pae4pm:~$ uname -a
> Linux pae4pm 3.8.0-31-generic #46-Ubuntu SMP Tue Sep 10 19:56:49 UTC
> 2013 i686 i686 i686 GNU/Linux
>
> I think your zRAM 'came along as a dependency for something'.
> Maybe you
> have installed some ppa or other special repository to get new
> kernels
> or other new packages. What version is the kernel in your system?
>
> Best regards
> Nio
>
>
> On 2013-09-28 01:06, John Hupp wrote:
>
> The news/announcements concerning Saucy tend to say
> something "new in
> Saucy ... zRAM."
>
> But zram-config is installed in my Raring i386 standard desktop
> installation, and I didn't install it unless it came along as a
> dependency for something.
>
> On 9/27/2013 6:29 PM, Nio Wiklund wrote:
>
> Sorry, I overlooked that John is running Raring. I
> didn't think zRAM was
> used in Raring, but of course, John can install and run
> it. I'm glad you
> corrected that mistake by me.
>
> Best regards
> Nio
>
> On 2013-09-28 00:08, Phill Whiteside wrote:
>
> hi Nio,
>
> he is running Raring. The bug we see in Saucy on
> 1227202 is totally
> un-related to the sudo parted -l issue.
>
> Getting the race issue sorted out on un-mounting the
> zram areas is what
> the bug fix is. With all the tests I've done, the
>
> Error: /dev/zram0: unrecognised disk label
>
> Error: /dev/zram1: unrecognised disk label
>
> Has remained until I used the 3.12rc kernel. We will
> go battle that
> issue on Monday to see if we can find the fix. Also do
> read
> https://bugs.launchpad.net/__ubuntu/+source/linux/+bug/__1215379
> <https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1215379>
> as we
> may be barking up the wrong tree with zram, and
> should be using zswap.
>
> Joe cannot tell us which is better to use, just that
> zswap was in the
> 3.11.2 upstream kernel which has been imported into
> the latest
> 3.11.0-9.16 kernel.
>
> It was Unit193 who pointed that issue out, and
> whilst getting the race
> crash sorted out, it appears that zswap is the
> updated system.
>
> Regards,
>
> Phill.
>
>
> On 27 September 2013 22:54, Nio Wiklund
> <nio.wiklund at gmail.com <mailto:nio.wiklund at gmail.com>
> <mailto:nio.wiklund at gmail.com
> <mailto:nio.wiklund at gmail.com>>__> wrote:
>
> 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.
>
> https://bugs.launchpad.net/__bugs/1227202
> <https://bugs.launchpad.net/bugs/1227202>
>
> 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
> Nio
>
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