September 2011 - luv-main

Re: [luv-main] Bought a laptop with optimus, doesn't work (nice false advertising nvidia). Now wanting to murder nvidia via Open Letter.
by Toby Corkindale 14 Sep '11

14 Sep '11

On 12/09/11 18:56, Luke Martinez wrote: > Should I look at all release notes for drivers for every bit of > hardware, expecting someone to do that is ridiculous. I did a bit of > research on my card 555GTM + linux, i had linux drivers etc. Any sane > person would expect it to work. Indeed, any sane person would *expect* it to work, but then, sane people probably go out and buy machines with OSX or Windows pre-installed. This is why I don't try and persuade friends, family or even random strangers to use Linux on their desktops any more. There's always something that doesn't quite work. Ubuntu have gone a long way towards trying to integrate the work of third-party binary drivers into a system which normal users can cope with, but stuff is still miles away from being reliably usable on 99% of modern systems :(

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what's a good Jabber server?
by Russell Coker 14 Sep '11

14 Sep '11

I've been using ejabberd for a while, but it's painful. It has an extra daemon process used for mysterious Erlang stuff, it binds to more ports than it should, and it doesn't work without a lot of fiddling. I'd like a simple jabber server that uses plain text files to tell it the IP address to bind to and the valid user-names and to have a simple utility for generating passwords like the htpasswd program that comes with Apache. Getting Apache going is MUCH easier than getting ejabberd going, but Apache is a much more complex program. Back in the days of Debian/Lenny I investigated all the options and determined that ejabberd was best. I may have been wrong then, but even if I was right there is scope for other programs to have been improved. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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Re: [luv-main] Bought a laptop with optimus, doesn't work (nice false advertising nvidia). Now wanting to murder nvidia via Open Letter.
by Luke Martinez 14 Sep '11

14 Sep '11

I am a Mailing list noob... o.O Well this Dell XPS 15 laptop has everything except for Nvidia working. Suspend, wifi (Linux 3.0+), touchpad (3.1+), bluetooth, Fn+turn off touchpad. Although touchpad + wifi was a problem when i installed Fedora which had an earlier kernel. Regards, Luke On Wed, Sep 14, 2011 at 3:26 PM, Luke Martinez <me(a)luke.asia> wrote: > Well this Dell XPS 15 laptop has everything except for Nvidia working. > Suspend, wifi (Linux 3.0+), touchpad (3.1+), bluetooth, Fn+turn off > touchpad. > > Although touchpad + wifi was a problem when i installed Fedora which had an > earlier kernel. > > Regards, > Luke > > > On Wed, Sep 14, 2011 at 3:19 PM, James Harper < > james.harper(a)bendigoit.com.au> wrote: > >> > On 14/09/11 14:45, Craig Sanders wrote: >> > > support for laptop-specific stuff (graphics switching, etc) on linux >> > > is still problematic. If you choose your laptop carefully, it works >> > > great. But if you just buy one without researching it thoroughly, >> > > you'll probably be disappointed. >> > >> > Most people I know who aren't serious techies just have laptops. I >> have gone >> > through quite a lot of laptops too. >> > NONE of them have managed to work out-of-the-box properly with Linux. >> > Usual suspects are the wifi or suspend not working, but if it's not >> that, it's >> > something else like sound or accelerated video. >> > >> >> The second-hand market is great for Linux use. Unless you want something >> exceptionally fast and shiny and new, a 3 year old laptop will probably >> work just great with some more memory and maybe a new battery. I was >> recently gifted an old HP nx7010 (which is maybe a little older than 3 >> years) and Ubuntu "just worked" with the exception of tv out which >> required a tiny bit of fiddling. Wireless, graphics, touch pad, all >> good. When doing repairs on laptops I often boot off a Linux USB stick >> to test things and haven't had problems except for some very new models, >> although a USB recovery stick hardly equates to production use - I'm >> guessing if I wanted accelerated graphics I might have more trouble with >> the newer stuff. >> >> James >> >> >> >> _______________________________________________ >> luv-main mailing list >> luv-main(a)lists.luv.asn.au >> http://lists.luv.asn.au/listinfo/luv-main >> > >

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Re: [luv-main] backkuppc and ZFS (was Re: Back ups)
by Toby Corkindale 14 Sep '11

14 Sep '11

On 10/09/11 14:57, Daniel Pittman wrote: > On Fri, Sep 9, 2011 at 21:41, Craig Sanders<cas(a)taz.net.au> wrote: >> On Sat, Sep 10, 2011 at 12:30:07PM +1000, Tim Connors wrote: >>>> I woke up yesterday morning to find my system load avg at over 100 - due >>>> [...] >>>> worse, it crashed later even without mlocate running. backuppc scheduled >>> >>> It's true, the linux VMM is a bit shit. A load of 100 is just a slight >>> bit crap. >> >> all waiting for IO. it's hardly linux' fault that some process is going >> apeshit creating a hard-link farm. > > What puzzles me in this discussion is that linking and deleting, in > BackupPC, are a single-threaded operation. One Perl process running, > chewing through one file system operation after another. So, while I > have no doubt it caused this, it feels like there is some underlying > problem lurking in there, waiting for the next time something has a > similar meta-data heavy set of operations happening... For what it's worth, we've seen issues with BackupPC causing excessive laod and nearly killing machines in a manner much like this too. I wasn't investigating that one so can't provide much useful info, other than another data point of "it does happen". Toby

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ZFS, btrfs, etc benchmarked by Postgres
by Toby Corkindale 13 Sep '11

13 Sep '11

As I threatened to do earlier today, I've run ZFS up against the PostgreSQL benchmark, along with ext4 and ZFS. (You may remember I did this a while back, looking at ext2/3/4, btrfs and xfs) I ran the results on Ubuntu 11.04 with Pg 9.0 and Ubuntu 11.10 beta with Pg 9.1. In the following results, the first combo is called "natty" and the second one "oneiric". The latter combination showed a considerable performance improvement overall - although I didn't investigate to find out whether this was due to kernel improvements, postgres improvements, or virtio improvements. The results are measured in transactions-per-second, with higher numbers being better. ext4 (data=writeback,relatime): natty: 248 oneiric: 297 ext4 (data=writeback,relatime,nobarrier): natty: didn't test oneiric: 1409 xfs (relatime): natty: didn't test oneiric: 171 btrfs (relatime): natty: 61.5 oneiric: 91 btrfs (relatime,nodatacow): natty: didn't test oneiric: 128 zfs (defaults): natty: 171 oneiric: 996 Conclusion: Last time I ran these tests, xfs and ext4 pulled very similar results, and both were miles ahead of btrfs. This time around, ext4 has managed to get a significantly faster result than xfs. However we have a new contender - ZFS performed *extremely* well on the latest Ubuntu setup - achieving triple the performance of regular ext4! I am suspicious that ZFS may not be using any "barrier" coding though - and if ext4 has those disabled, it surpasses even ZFSs high score. Oddly, ZFS performed wildly differently on ubuntu 11.04 vs 11.10b. I can't explain this. Any ideas? Cheers, Toby

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iptables to block inbound connections by UID
by Russell Coker 13 Sep '11

13 Sep '11

ejabberd likes to listen on multiple TCP ports and bind to 0.0.0.0. I can't stop it from binding because then it can't do it's own IPC but I don't want to expose it to the world. Below is the script that I am currently using, the result of this is that the client that connects to one of the undesired ports just gets no response. I can't use -mowner in an INPUT chain. Is there any way I can convert a SYN/ACK to a RST on the way out? iptables -F OUTPUT iptables -A OUTPUT -d 192.168.0.0/16 -j ACCEPT iptables -A OUTPUT -d 127.0.0.0/8 -j ACCEPT # limit ejabberd iptables -A OUTPUT -p tcp --sport 5222 -j ACCEPT iptables -A OUTPUT -p tcp --sport 5269 -j ACCEPT iptables -A OUTPUT -p tcp -mowner --uid-owner 203 -j REJECT --reject-with tcp- reset -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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Re: [luv-main] backkuppc and ZFS (was Re: Back ups)
by Toby Corkindale 13 Sep '11

13 Sep '11

On 12/09/11 13:20, Jason White wrote: > Peter Ross<Peter.Ross(a)bogen.in-berlin.de> wrote: > >> Every snapshot is like a filesystem, with its own metadata and data. >> >> They only "interfere" because they may point to the same (unchanged) >> data. But there is no backtracking or reconstruction from one >> snapshot to the other. > > My understanding is that this is also true of Btrfs snapshots. It should be > noted that most of the metadata are not copied when a snapshot is created, > judigng by the speed of this operation. > > Regarding ZFS, it is my impression that all of the people who understand the > internals of the file system and its implementation are Sun/Solaris > developers, some of whom may have left after the acquisition by Oracle. I > don't know what situation this creates as to the availability of expertise (at > the level of understanding the code well enough to debug it) for projects > porting it to BSD and Linux. > > Btrfs does appear to be gaining contributions from a variety of sources, > prominently Red Hat, so the expertise isn't concentrated in the hands of any > single corporation. Last time I checked, Btrfs had sucky performance, especially for PostgreSQL loads. (Even with the "nodatacow" option enabled) How does the DKIM-based ZFS look? Otherwise I'm curious enough that I'll run up a test myself. Cheers, Toby

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