Linuxers February 2013

linuxers@mm.ilug-bom.org.in

20 participants
19 discussions

Re: [ILUG-BOM] How to detect a power failure?
by Arun Khan 18 Feb '13

18 Feb '13

Changed the subject for it to be relevant to the OP On Sun, Feb 17, 2013 at 11:58 PM, Joel Rebello <joelmadzu(a)gmail.com> wrote: ........... trimmed a lot of the irrelevant quote from the *digest* message > Hey, > > Im from Vasai, where we have frequent powercuts. I run a linux box at home > which basically acts as my home server(box) > I currently use the GPIO pin on my wifi router(running openwrt) to 'sense' > powercuts, which in turn powers off the box and turns … [View More]

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How to detect a power failure?
by J T Dsouza 18 Feb '13

18 Feb '13

On Friday 15 February 2013 19:57:59 Binand Sethumadhavan wrote: > I am thinking of something like a mobile charger that would plug in a > regular 3-pin plug at one end and a computer at the other, and some > software/sensor combo that would read the (DC) voltage at the computer end. > If there is no voltage, there is no power in the mains and ergo - we are in > the middle of a power outage, so take action. Know of something along these > lines? My mails to the list are … [View More]

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Re: [ILUG-BOM] Linuxers Digest, Vol 104, Issue 7
by Joel Rebello 17 Feb '13

17 Feb '13

On Sun, Feb 17, 2013 at 10:30 PM, <linuxers-request(a)mm.ilug-bom.org.in>wrote: > Send Linuxers mailing list submissions to > linuxers(a)mm.ilug-bom.org.in > > To subscribe or unsubscribe via the World Wide Web, visit > http://mm.ilug-bom.org.in/mailman/listinfo/linuxers > or, via email, send a message with subject or body 'help' to > linuxers-request(a)mm.ilug-bom.org.in > > You can reach the person managing the list at > … [View More]linuxers-owner(a)mm.ilug-bom.org.in > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Linuxers digest..." > > > Today's Topics: > > 1. Re: Ubuntu Global Jam Mumbai 2013 for Ubuntu Raring Ringtail > (Rigved Rakshit) > 2. Re: How to detect a power failure? (gnulinuxist(a)gmail.com) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 17 Feb 2013 02:21:02 +0530 > From: Rigved Rakshit <r.phate(a)gmail.com> > To: mumbailug(a)googlegroups.com, Mumbai LUG > <linuxers(a)mm.ilug-bom.org.in> > Subject: Re: [ILUG-BOM] Ubuntu Global Jam Mumbai 2013 for Ubuntu > Raring Ringtail > Message-ID: > < > CAEuhoydO7nY5nHW_4vpj96GKgBNRq4sa7370WbC+UK7fz4DWmA(a)mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > > The dates are tentative because Canonical themselves have not released > > the dates. Once that is done, I will let you guys know the final > > dates. This is one of the "problems" of planning events ahead of time. > > But I am hoping that this will give everyone enough time to plan and > > attend the event! > > Dates have been finalised. Now, it will be on March 2 and 3. Here is the > event page: http://loco.ubuntu.com/events/indian-team/2235/detail/ . As of > now, I have kept the event only on Saturday and Sunday. But if people are > interested, I can keep it on Friday as well. > > Best Regards, > Rigved Rakshit > > > ------------------------------ > > Message: 2 > Date: Sun, 17 Feb 2013 14:54:55 +0000 > From: "gnulinuxist(a)gmail.com" <gnulinuxist(a)gmail.com> > To: "linuxers(a)mm.ilug-bom.org.in" <linuxers(a)mm.ilug-bom.org.in> > Subject: Re: [ILUG-BOM] How to detect a power failure? > Message-ID: <5120ef43.8148420a.567d.ffffb7ad(a)mx.google.com> > Content-Type: TEXT/PLAIN; charset=UTF-8 > > > > -----Original Message----- > From: Arun Khan > Sent: 16/02/2013, 01:45 > To: GNU/Linux Users Group, Mumbai, India > Subject: Re: [ILUG-BOM] How to detect a power failure? > > > On Fri, Feb 15, 2013 at 7:57 PM, Binand Sethumadhavan <binand(a)gmail.com> > wrote: > > I am thinking of something like a mobile charger that would plug in a > > regular 3-pin plug at one end and a computer at the other, and some > > software/sensor combo that would read the (DC) voltage at the computer > end. > > If there is no voltage, there is no power in the mains and ergo - we are > in > > the middle of a power outage, so take action. Know of something along > these > > lines? > > > > (idea is to detect power failures, while powered by a "dumb" UPS unit - > one > > that cannot communicate with the a computer. Any other > > solutions/suggestions?). > > > > Good idea. You could use one of those AC Mains to USB > adapter/charger; which I think gives out 5V on the USB power line. A > USB cable into the computer USB port should be a good starting. > > -- Arun Khan > -- > > This usb idea is good. A usb powered device can be used where power comes > externally for on/off and the system gives signal to detect that device is > down. A cheap 200 rupees usb lan can be opened and modified. Every few > minutes, the output of ifconfig can be grepped to detect the presence of > eth(n). Battery power detect option is only in laptops. > > Hey, Im from Vasai, where we have frequent powercuts. I run a linux box at home which basically acts as my home server(box) I currently use the GPIO pin on my wifi router(running openwrt) to 'sense' powercuts, which in turn powers off the box and turns it back on when power resumes. Let me know if you'd like more details on the setup and code, I'd be happy to share :) Regards, Joel Rebello -- Be yourself , just better. [View Less]

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Re: [ILUG-BOM] How to detect a power failure?
by gnulinuxist＠gmail.com 17 Feb '13

17 Feb '13

-----Original Message----- From: Arun Khan Sent: 16/02/2013, 01:45 To: GNU/Linux Users Group, Mumbai, India Subject: Re: [ILUG-BOM] How to detect a power failure? On Fri, Feb 15, 2013 at 7:57 PM, Binand Sethumadhavan <binand(a)gmail.com> wrote: > I am thinking of something like a mobile charger that would plug in a > regular 3-pin plug at one end and a computer at the other, and some > software/sensor combo that would read the (DC) voltage at the computer end. > If there … [View More]

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Unable to reactivate a RAID10 mdadm device
by Arun Khan 12 Feb '13

12 Feb '13

Recovery OS -- System Rescue CD v 2.8.0 Production OS - Debian Squeeze (6) 2.6.32 stock kernel, using mdadm raid /dev/md0 in raid level RAID10 - members /dev/sdb1, /dev/sdc1, /dev/sdd1, /dev/sde1 all with partion id=fd HDD /dev/sdb went bad, replaced it with another disk with same size partion (id=fd) using System Rescue CD v2.8.0 1. System Rescue CD recognized the md devices but it comes up as 'inactive' Searched for possible solutions and I have tried several things including zeroing the … [View More]super block and adding them back to the array. Still unable to bring back /dev/md0 with all 4 partions in active mode. I have included below, the entire transcript of the commands I have tried to recover /dev/md0 I have data on /dev/md0 that I need. I do have back ups of critical files (but not all). I prefer solving the problem v/s recreating the /dev/md0 from scratch. Any help in solving this problem would be highly appreciated. TIA, -- Arun Khan --------------- transcript of mdadm activity with System Rescue CD v2.8.0 ---------------- # mdadm -V mdadm - v3.1.4 - 31st August 2010 # cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : inactive sdd1[2] sde1[3] 312574512 blocks super 1.0 # mdadm -S /dev/md0 mdadm: stopped /dev/md0 # cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] unused devices: <none> # mdadm -v -v -A /dev/md0 -R /dev/sd[bcde]1 mdadm: looking for devices for /dev/md0 mdadm: /dev/sdb1 is identified as a member of /dev/md0, slot 0. mdadm: /dev/sdc1 is identified as a member of /dev/md0, slot 1. mdadm: /dev/sdd1 is identified as a member of /dev/md0, slot 2. mdadm: /dev/sde1 is identified as a member of /dev/md0, slot 3. mdadm: added /dev/sdb1 to /dev/md0 as 0 mdadm: added /dev/sdc1 to /dev/md0 as 1 mdadm: added /dev/sde1 to /dev/md0 as 3 mdadm: added /dev/sdd1 to /dev/md0 as 2 mdadm: failed to RUN_ARRAY /dev/md0: Input/output error mdadm: Not enough devices to start the array. # cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : inactive sdd1[2] sde1[3] 312574512 blocks super 1.0 unused devices: <none> from /var/log/messages Feb 12 06:13:59 sysresccd kernel: [ 7593.339015] md: md0 stopped. Feb 12 06:13:59 sysresccd kernel: [ 7593.374016] md: bind<sdb1> Feb 12 06:13:59 sysresccd kernel: [ 7593.374417] md: bind<sdc1> Feb 12 06:13:59 sysresccd kernel: [ 7593.374604] md: bind<sde1> Feb 12 06:13:59 sysresccd kernel: [ 7593.374869] md: bind<sdd1> Feb 12 06:13:59 sysresccd kernel: [ 7593.374899] md: kicking non-fresh sdc1 from array! Feb 12 06:13:59 sysresccd kernel: [ 7593.374903] md: unbind<sdc1> Feb 12 06:13:59 sysresccd kernel: [ 7593.379016] md: export_rdev(sdc1) Feb 12 06:13:59 sysresccd kernel: [ 7593.379041] md: kicking non-fresh sdb1 from array! Feb 12 06:13:59 sysresccd kernel: [ 7593.379044] md: unbind<sdb1> Feb 12 06:13:59 sysresccd kernel: [ 7593.386010] md: export_rdev(sdb1) Feb 12 06:13:59 sysresccd kernel: [ 7593.387382] md/raid10:md0: not enough operational mirrors. Feb 12 06:13:59 sysresccd kernel: [ 7593.387410] md: pers->run() failed ... # mdadm -D /dev/md0 /dev/md0: Version : 1.0 Creation Time : Fri Apr 29 04:27:04 2011 Raid Level : raid10 Used Dev Size : 156287232 (149.05 GiB 160.04 GB) Raid Devices : 4 Total Devices : 2 Persistence : Superblock is persistent Update Time : Mon Feb 11 13:43:52 2013 State : active, FAILED, Not Started Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Layout : near=2 Chunk Size : 32K Name : brahmaputra:0 UUID : f2d4e898:2e026f85:244a7e9c:908e1af7 Events : 783527 Number Major Minor RaidDevice State 0 0 0 0 removed 1 0 0 1 removed 2 8 49 2 active sync /dev/sdd1 3 8 65 3 active sync /dev/sde1 # mdadm -E /dev/sdc1 /dev/sdc1: Magic : a92b4efc Version : 1.0 Feature Map : 0x1 Array UUID : f2d4e898:2e026f85:244a7e9c:908e1af7 Name : brahmaputra:0 Creation Time : Fri Apr 29 04:27:04 2011 Raid Level : raid10 Raid Devices : 4 Avail Dev Size : 312574512 (149.05 GiB 160.04 GB) Array Size : 625148928 (298.09 GiB 320.08 GB) Used Dev Size : 312574464 (149.05 GiB 160.04 GB) Super Offset : 312574640 sectors State : clean Device UUID : 2fbc103e:ca40e0c2:b8e4d64f:0fbc7b94 Internal Bitmap : -8 sectors from superblock Update Time : Mon Feb 11 13:43:52 2013 Checksum : 2e8e9fad - correct Events : 0 Layout : near=2 Chunk Size : 32K Device Role : spare Array State : ..AA ('A' == active, '.' == missing) # mdadm -E /dev/sdb1 /dev/sdb1: Magic : a92b4efc Version : 1.0 Feature Map : 0x1 Array UUID : f2d4e898:2e026f85:244a7e9c:908e1af7 Name : brahmaputra:0 Creation Time : Fri Apr 29 04:27:04 2011 Raid Level : raid10 Raid Devices : 4 Avail Dev Size : 312574512 (149.05 GiB 160.04 GB) Array Size : 625148928 (298.09 GiB 320.08 GB) Used Dev Size : 312574464 (149.05 GiB 160.04 GB) Super Offset : 312574640 sectors State : clean Device UUID : e27c187b:9004cb93:5bb05639:164822cd Internal Bitmap : -8 sectors from superblock Update Time : Mon Feb 11 13:43:52 2013 Checksum : 5ea77bd0 - correct Events : 0 Layout : near=2 Chunk Size : 32K Device Role : spare Array State : ..AA ('A' == active, '.' == missing) # mdadm -E /dev/sde1 /dev/sde1: Magic : a92b4efc Version : 1.0 Feature Map : 0x1 Array UUID : f2d4e898:2e026f85:244a7e9c:908e1af7 Name : brahmaputra:0 Creation Time : Fri Apr 29 04:27:04 2011 Raid Level : raid10 Raid Devices : 4 Avail Dev Size : 312574512 (149.05 GiB 160.04 GB) Array Size : 625148928 (298.09 GiB 320.08 GB) Used Dev Size : 312574464 (149.05 GiB 160.04 GB) Super Offset : 312574640 sectors State : clean Device UUID : 78fc82bc:2eb18f07:56c98922:7639269e Internal Bitmap : -8 sectors from superblock Update Time : Mon Feb 11 13:43:52 2013 Checksum : ce19a703 - correct Events : 783527 Layout : near=2 Chunk Size : 32K Device Role : Active device 3 Array State : ..AA ('A' == active, '.' == missing) # mdadm -E /dev/sdd1 /dev/sdd1: Magic : a92b4efc Version : 1.0 Feature Map : 0x1 Array UUID : f2d4e898:2e026f85:244a7e9c:908e1af7 Name : brahmaputra:0 Creation Time : Fri Apr 29 04:27:04 2011 Raid Level : raid10 Raid Devices : 4 Avail Dev Size : 312574512 (149.05 GiB 160.04 GB) Array Size : 625148928 (298.09 GiB 320.08 GB) Used Dev Size : 312574464 (149.05 GiB 160.04 GB) Super Offset : 312574640 sectors State : clean Device UUID : 1dce2f63:fef488cb:1a362c57:7ed908ac Internal Bitmap : -8 sectors from superblock Update Time : Mon Feb 11 13:43:52 2013 Checksum : 7b44c944 - correct Events : 783527 Layout : near=2 Chunk Size : 32K Device Role : Active device 2 Array State : ..AA ('A' == active, '.' == missing) # mdadm --zero-superblock /dev/sdb1 # mdadm -E /dev/sdb1 mdadm: No md superblock detected on /dev/sdb1. # mdadm /dev/md0 --add /dev/sdb1 mdadm: add new device failed for /dev/sdb1 as 4: Invalid argument from /var/log/messages Feb 12 06:52:26 sysresccd kernel: [ 9900.298880] md0: ADD_NEW_DISK not supported [View Less]

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Fwd: [MumPy] hackathon at CAMP on Saturday, 9th feb
by Mehul Ved 07 Feb '13

07 Feb '13

---------- Forwarded message ---------- From: Sanjay Bhangar <sanjaybhangar(a)gmail.com> Date: Thu, Feb 7, 2013 at 1:51 PM Subject: [MumPy] hackathon at CAMP on Saturday, 9th feb To: mumpy(a)googlegroups.com Hey all, Sorry for the delayed notice on this -- We're hosting a hackathon at CAMP [1] [2] on Saturday 9th Feb, 3pm onwards. The broad agenda is to build an open platform for book-sharing in the city. A few artist's organizations have come together as the Umbrella group to … [View More]

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[Commercial] A sneak peek into OSFY mega anniversary issue (Feb 2013
by Priyanka Sarkar 07 Feb '13

07 Feb '13

Dear Members, OSFY's mega 10th Anniversary issue (Feb 2013) brings you a melange of interesting articles on your platter. Special Read for Developers: --Protecting Systems Intents in Android --Implementing HTML5 WebSockets Using Java --Dynamic Program Analysis Using Valgrind: A Jump-Start Guide Admin's Domain --A Peek Into Best open source security tools --Combat virtual threats with IPCop Firewall --A look at top 10 open source Web log Analysers For U & Me: It's the stuff for everyone … [View More]

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Serious Problems With USB Controller in Raspberry Pi
by Siji Sunny 06 Feb '13

06 Feb '13

It seems like the usb controller used* *in Rspberry pi SOC (Broadcom BCM2835) has some serious issues , since it can only supply low amount of current to its USB devices (Approximately 140 mA). This will cause continues restart of RPI specially while connecting USB Network Card, USB Modem or GPS devices. This may be a bug in USB driver, which has not fixed yet and may not be an easy task because : (Ref: http://hardware.slashdot.org/story/12/08/24/2228251/serious-problems-with-u… ) 1) … [View More]

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Fwd: Will you be at LibrePlanet? Register today for March 23-24
by Shahid Farooqui 01 Feb '13

01 Feb '13

---------- Forwarded message ---------- From: Free Software Foundation <info(a)fsf.org> Date: Fri, Feb 1, 2013 at 4:40 AM Subject: Will you be at LibrePlanet? Register today for March 23-24 To: Shahid Farooqui <shahidfarooqui(a)gmail.com> [image: Register now]<http://libreplanet.org/wiki/LibrePlanet:Conference/2013> Hi Shahid, We're excited to announce that registration is now open for LibrePlanet 2013: "Commit Change."<http://libreplanet.org/wiki/LibrePlanet:Conference/… [View More]

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Linuxers February 2013