- luv-main - luv.asn.au

Orbital simulation
by Russell Coker 26 Sep '16

26 Sep '16

Is there a good free orbital simulator for Linux? I don't want a game like KSP but a simulation of orbits without much need for fancy graphics. I am wondering what the orbit of a ring would be like (EG a Dyson ring) and whether it's plausible to make such a ring or whether a set of disconnected sattelites in the same orbit is required. -- Sent from my Nexus 6P with K-9 Mail.

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another outage
by Russell Coker 24 Sep '16

24 Sep '16

The virtual machine running the LUV server was killed by the kernel OOM 4 hours ago. I didn't immediately notice because the VM running my Jabber server (which notifies me of system problems) was also killed). When we had the last problem I converted the virtual machines from Xen to KVM. With KVM the VMs are regular Linux processes and they share the same memory as regular processes. So if another process allocates too much RAM then it may cause KVM memory allocation to fail. Also if the entire system runs out of RAM the kernel may stupidly decide to kill the KVM instance instead of something else. I think that part of the problem was that BOINC was configured to use up to 90% of system RAM. That was an OK setting for a Xen server where the Dom0 had nothing of note running other than BOINC and the virtual machines had RAM reserved. When running KVM this wasn't a suitable setting. I've configured BOINC to only use 40% of RAM and increased swap size. This shouldn't happen again. Also I'm going to move the Jabber server to the Dom0 so that if the DomUs die then I can still get alerts. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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ZFS error logging
by Russell Coker 23 Sep '16

23 Sep '16

Below is part of the output of "zpool status". It seems that sdr is defective, it has a steadily increasing number of checksum errors. Would the "resilvered 763M" part be about the 121 checksum errors? If so does that mean each checksum error required resilvering on average 6M of data? The kernel message log has NOTHING about this. I'm used to Ext* and BTRFS which give kernel message log entries about filesystem errors. Can ZFS be configured to give similar logging? As an aside I've written a mon module for monitoring for such ZFS errors. I'll release it sometime soon. But I'd be happy to give a version that's quite usable although not ready for full release to anyone who wants it. status: One or more devices has experienced an unrecoverable error. An attempt was made to correct the error. Applications are unaffected. action: Determine if the device needs to be replaced, and clear the errors using 'zpool clear' or replace the device with 'zpool replace'. see: http://zfsonlinux.org/msg/ZFS-8000-9P scan: resilvered 763M in 0h0m with 0 errors on Thu Aug 18 14:48:53 2016 config: NAME STATE READ WRITE CKSUM server ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 sdj ONLINE 0 0 0 sdk ONLINE 0 0 0 sdl ONLINE 0 0 0 sdm ONLINE 0 0 0 sdn ONLINE 0 0 0 sdo ONLINE 0 0 0 sdp ONLINE 0 0 0 sdq ONLINE 0 0 0 sdr ONLINE 0 0 121 -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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Postfix + Dovecot (+MySQL)
by Piers Rowan 22 Sep '16

22 Sep '16

Hi there, I set up a VM a couple of weeks back as a mail server. I can send email via web mail and I can get email in but I can't get it to relay. cat /etc/postfix/main.cf | grep restrictions # overcome chroot restrictions. The alternative, having a copy of # through Postfix. See the smtpd_recipient_restrictions parameter # relay mail to. See the smtpd_recipient_restrictions description in smtpd_relay_restrictions = permit_mynetworks,permit_sasl_authenticated,reject_unauth_destination mua_client_restrictions = permit_sasl_authenticated,reject mua_helo_restrictions = permit_sasl_authenticated,reject mua_sender_restrictions = permit_sasl_authenticated,reject smtpd_recipient_restrictions = permit_mynetworks,permit_sasl_authenticated,check_policy_service unix:/var/spool/postfix/postgrey/socket smtpd_recipient_restrictions = reject_invalid_hostname, reject_unknown_recipient_domain, reject_unauth_pipelining, permit_mynetworks, reject_unauth_destination, permit_sasl_authenticated, check_policy_service unix:/var/spool/postfix/postgrey/socket, reject_rbl_client zen.spamhaus.org, reject_rbl_client bl.spamcop.net, reject_rbl_client dnsbl.sorbs.net, reject_rbl_client cbl.abuseat.org, reject_rbl_client b.barracudacentral.org, reject_rbl_client dnsbl-1.uceprotect.net,permit cat /etc/postfix/master.cf | grep restrictions -o smtpd_client_restrictions=$mua_client_restrictions -o smtpd_helo_restrictions=$mua_helo_restrictions -o smtpd_sender_restrictions=$mua_sender_restrictions -o smtpd_recipient_restrictions=permit_sasl_authenticated,reject # -o smtpd_client_restrictions=$mua_client_restrictions # -o smtpd_helo_restrictions=$mua_helo_restrictions # -o smtpd_sender_restrictions=$mua_sender_restrictions # -o smtpd_recipient_restrictions=permit_sasl_authenticated,reject -o smtpd_client_restrictions= -o smtpd_helo_restrictions= -o smtpd_sender_restrictions= -o smtpd_recipient_restrictions=permit_mynetworks,permit_sasl_authenticated,reject Any ideas? I'm not familiar with Postfix. Thanks Piers

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TCP rate/congestion control
by Toby Corkindale 19 Sep '16

19 Sep '16

I noticed that Windows 10 now uses CTCP as the default TCP congestion/rate control algorithm, but Linux still defaults to the old Cubic algorithm. CTCP doesn't appear to be available on Ubuntu LTS at the moment, but there's a whole host of others to choose from. Has anyone here worked out which is the best one to use on typical consumer internet links in Australia? (ie. ADSL with 4-12 mbps and only minor packet loss) Available options on Ubuntu Xenial: - bic - cubic - cdg - dctcp - diag - highspeed - htcp - hybla - illinois - lp - probe - reno - scalable - vegas - veno - westwood - yeah

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Can anyone make suggestions for training / learning resources wrt databases.
by h 18 Sep '16

18 Sep '16

Hi, I am a linux hobbyist. I have been using postgis for a while, at a hobby level, to provide data for web pages and for QGIS. I am reasonably confident writing sql statements, and being able to find the information I need to get the data I am after. There are two areas I have been unable to find information on: * Writing sql / script files * Structuring tables either within a database, or on a server The particular problems I have are: * I regularly update my tables from multiple csv files, all residing in the same folder. Currently I have a script with a hardwired path for each csv file. I would like to have a single 'variable' I could change to define the path to all the csvs. * I have a database which I have decided should contain three types of table - core definitions / lookups, - raw data and - derived data for specific tasks. I would like to create separate areas in the database / (server?) for each table type, or learn of other options for how the tables could be structured. I am NOT looking for specific answers to these problems, but rather some teaching / groundwork information about relational databases / sql / postgis concepts. I have seen training videos / websites covering writing queries and on database security, but cannot find anything on script files, or database structure. I suspect wrong terminology and poor google skills are to blame. Can anyone suggest web sites etc that provide information on either / both of these two topics? With thanks Hugh

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Re: OT: trains & demand tariffs [Was: outage]
by Anthony 17 Sep '16

17 Sep '16

On Tue, Sep 13, 2016 at 12:23 PM, Russell Coker via luv-main < luv-main(a)luv.asn.au> wrote: > Interesting. I've been wondering how difficult it would be to use some IP > enabled switches to control home energy use. If you had a meter on the > main > power that reports the power use to a Linux system then you could have it > turn > off non-essential devices and make your PCs stop running BOINC if power > use is > too high. > Hrrmm.. Well, the smart meters in Victoria are supposed to use the "Zigbee Power" version 1 protocol. I know that for the distribution company within the area I reside (Jemena), I need only log into their portal (which also allows me to browse my power usage data online up to four hours ago at an hourly resolution or so, and to download a CSV that has data going back to when the meter was installed), specify the MAC address and installer code of the Zigbee device I wish to pair with my meter, and then that device can receive information from my smart meter. This is primarily for "in home displays", but presumably there's gotta be a device that's linux friendly out there that talks Zigbee Power v1?

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NBN satelite setup
by zlinew9＠virginbroadband.com.au 17 Sep '16

17 Sep '16

I am just about to get this installed and I wonder if anyone has any exprience of setting this up. The ISP concerned uses PPPOE, would the standard debian install using the ISP's given login name and password be all that is required. I assume nameserver setup would be transparent similiar to using "usepeerdns" in a PPP set up. Also, this is Lindsay from NE Victoria, I am already on the luv list, for some reason though I I can no longer post anything from my original account, this has been on going for quite along time, ALL other email works OK from my original account. Using Linux since 1993, Lindsay

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Warzone 2100 on Debian
by Russell Coker 17 Sep '16

17 Sep '16

Debian has an older version of the game Warzone 2100, which among other things means that it misses the ability to use some data files developed for newer versions, the ability to have multiplayer games with Windows users (who download the latest version) and whatever features there are in the new version. The DDs responsible for the package haven't had time to package the newer version. NB this is no criticism of them, there are plenty of packages I haven't had time to maintain properly. I've done some work on packaging the latest version. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=814248 One issue is that I get the Qt related error described in the latest update to the above bug when I build the latest version. This error happens after the main binary is compiled, it's in a test program. Before you ask, I am not planning on removing tests from Debian packages. The attachment to that update has my latest files for the Debian package. If you download the attachment you can build warzone2100 on Debian/Unstable and most likely get the same Qt error I get. When I run the binary produced I find that it has every object that is movable (units and walls) move to random angles in 3D. Basically you have tanks breakdancing. I don't even know where to start debugging this, I've never done graphics programming on anything more advanced than a Z80. Would anyone like to help with this? -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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Change HDMI resolution via fbset?
by Toby Corkindale 13 Sep '16

13 Sep '16

Hi, I have a couple of Intel NUCs (dual core celeron CPUs, Intel chipsets including video (i915 kernel module)) that I'm trying to use for a project. To simplify matters I was going to use the framebuffer device for video output -- but the HDMI defaults to 1920x1080 and I'd really like to change the resolution to match the projector's native resolution, which is 1024x768. I've tried using fbset, as in: $ fbset -geometry 1024 768 1024 768 32 but rather than change the HDMI output, it just makes the console occupy a smaller part of the screen. How useless! I tried using fbset like this too: $ fbset 1024x768-32 (where that mode is listed in /etc/fb.modes) but it just threw some errors back. Am I doing it wrong? Or is it possible that the framebuffer device for this video device just doesn't let you change the resolution? I guess it's not a disaster if I install a minimal X setup, but first.. any suggestions for fbset?

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