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Linux basics presentation
by Max Yermakhanov 31 Jan '17

31 Jan '17

Hello, I run Toronto Enterprise DevOps user group and I'm looking for someone to present on Linux basics on April 13th in Toronto. Would you know anyone who might be interested? Thanks in advance, Max.

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Router advice sought
by Stewart Russell 31 Jan '17

31 Jan '17

So my WRT-350N decided to stop being a router last night and to start being a brick instead. All ports and WiFi appear to be dead. People have discussed the latest and greatest here - so what's the best basic router for: * enough wireless range for a smallish two storey house; * able to connect and configure about 15 wireless clients and 4 wired (one wired in a DMZ) * probably going to stick with stock firmware, as the Linksys one on the WRT-350N was pretty much okay for the last 8 years; and * would be nice if it wasn't unholy expensive, was available retail today, and was likely to last at least another 8 years. My network setup is very simple: just internal IPs assigned by MAC address via DHCP, and locked in the router. Yes, I manually copy /etc/hosts files about: don't judge. It worked fine until the router went kablooie. I'm wondering if I even need a router, though. The Sagemcom box from Teksavvy (rented from Bell) has WiFi and four LAN ports. What does having my own router do for me? Recommendations and advice welcomed. Assume I have no idea what I'm doing if you haven't already. Thanks in advance Stewart

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Harddisk recommendation?
by William Park 31 Jan '17

31 Jan '17

I've been using leftover harddisks as BTRFS RAID1 storage, and I'm thinking about replacing them with large disks. Which harddisks would you recommend? Looking at Canada Computers and Newegg, there are lots of new colors and models. -- William

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Crashes
by Giles Orr 31 Jan '17

31 Jan '17

My primary machine is crashing with increasing frequency. The commonest error I'm seeing in the log looks like this: Jan 29 18:29:39 toshi7 kernel: nouveau 0000:01:00.0: DRM: suspending kernel object tree... Jan 29 18:30:00 toshi7 kernel: NMI watchdog: BUG: soft lockup - CPU#3 stuck for 23s! [kscreenlocker_g:19647] Jan 29 18:30:00 toshi7 kernel: Modules linked in: fuse uas usb_storage rfcomm ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_broute bridge stp llc ebtable_nat ip6table_nat nf_conntrack ... I realize that I'm probably not giving enough information, but pasting large chunks of log files would be just as counterproductive in its own way. I've seen this one A LOT - and sometimes I get it and the machine goes hours (but not days) before crashing. So ... is kscreenlocker likely to be the problem here? When I searched for "BUG soft lockup CPU stuck for" on Google, the top result had exactly the same number of seconds, and said that replacing the power supply fixed the problem. Which is a step I'd probably be willing to take, but this isn't a desktop, it's a laptop. So I'd want to be very sure as the power supply is unique to this machine (if it's available at all) and probably quite expensive. The processor: Intel(R) Core(TM) i7-3610QM CPU @ 2.30GHz (4594 bogomips) current speed: 1274MHz, 4 cores, 8 threads While it's not a current gen processor, this is still a good machine and I'd rather fix it than toss it. Got an immediate crash this morning, and to my surprise the error was very different: Jan 31 07:56:35 toshi7 kernel: ------------[ cut here ]------------ Jan 31 07:56:35 toshi7 kernel: kernel BUG at lib/radix-tree.c:769! Jan 31 07:56:35 toshi7 kernel: invalid opcode: 0000 [#1] SMP Jan 31 07:56:35 toshi7 kernel: Modules linked in: uas usb_storage rfcomm ip6t_rpfilter ip6t_REJECT nf_reject _ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_nat nf_conntrack_ipv6 ... Finally, I'm also getting this periodically: Jan 28 08:49:52 toshi7 kernel: CPU2: Core temperature above threshold, cpu clock throttled (total events = 1 ) Jan 28 08:49:52 toshi7 kernel: CPU6: Core temperature above threshold, cpu clock throttled (total events = 1) Jan 28 08:49:52 toshi7 kernel: CPU7: Package temperature above threshold, cpu clock throttled (total events = 1) Jan 28 08:49:52 toshi7 kernel: CPU4: Package temperature above threshold, cpu clock throttled (total events = 1) Jan 28 08:49:52 toshi7 kernel: CPU1: Package temperature above threshold, cpu clock throttled (total events = 1) Jan 28 08:49:52 toshi7 kernel: CPU5: Package temperature above threshold, cpu clock throttled (total events = 1) Jan 28 08:49:52 toshi7 kernel: CPU3: Package temperature above threshold, cpu clock throttled (total events = 1) Jan 28 08:49:52 toshi7 kernel: CPU0: Package temperature above threshold, cpu clock throttled (total events = 1) Jan 28 08:49:52 toshi7 kernel: CPU6: Package temperature above threshold, cpu clock throttled (total events = 1) Jan 28 08:49:52 toshi7 kernel: mce: [Hardware Error]: Machine check events logged Jan 28 08:49:52 toshi7 kernel: CPU2: Package temperature above threshold, cpu clock throttled (total events = 1) Jan 28 08:49:52 toshi7 kernel: mce: [Hardware Error]: Machine check events logged Jan 28 08:49:52 toshi7 kernel: CPU6: Core temperature/speed normal Jan 28 08:49:52 toshi7 kernel: CPU2: Core temperature/speed normal Jan 28 08:49:52 toshi7 kernel: CPU4: Package temperature/speed normal Jan 28 08:49:52 toshi7 kernel: CPU5: Package temperature/speed normal Jan 28 08:49:52 toshi7 kernel: CPU1: Package temperature/speed normal Jan 28 08:49:52 toshi7 kernel: CPU3: Package temperature/speed normal Jan 28 08:49:52 toshi7 kernel: CPU7: Package temperature/speed normal Jan 28 08:49:52 toshi7 kernel: CPU0: Package temperature/speed normal Jan 28 08:49:52 toshi7 kernel: CPU2: Package temperature/speed normal Jan 28 08:49:52 toshi7 kernel: CPU6: Package temperature/speed normal This suggests that it's overheating, throttling, and recovering pretty much instantaneously: my thought is that it's probably not a problem, but I thought I should check. How should I proceed from here: - the processor is going funny, replace it - junk the laptop, it's toast - debug further (how?) - replace the power supply - uninstall kscreenlocker and see what happens -- Giles http://www.gilesorr.com/ gilesorr(a)gmail.com

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NVIDIA SHIELD Tablet K1
by Michael Galea 23 Jan '17

23 Jan '17

Does anyone own an NVIDIA SHIELD Tablet K1 and can they recommend it? I am looking for a recommendation of this tablet for the purpose of web and email. I have heard that it being a gaming tablet with four cores at 2.2 Ghz, it should be overkill for the intended use. But that is just what I want. If anyone knows of a better android based tablet, please let me know. -- Michael Galea

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Boot problem
by Michael Galea 23 Jan '17

23 Jan '17

I am seeing a problem at boot time that has appeared in kernels after 4.3.0-1-amd64. My system will boot, show the available debian kernels, select the latest and then jump into initramrs. It claims it can not mount dev and other partitions and, indeed, an ls on the mounted /dev/sda1 shows that my esata drive has been mounted as root! To boot properly I must power off the esata, boot and wait until the boot is proceeding from the system disk, then power up the esata. The bios boot order is set to boot from the (correct) system disk. /etc/fstab is set to boot using UUIDs, and all UUIDs are correct. The esata drive is not bootable. Can anyone suggest something to look at or try? I would expect that if grub was able to show me my images it would be able to load them, even if the esata was available. -- Michael Galea

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War Story: UEFI Boot Failure and Fix
by Scott Sullivan 19 Jan '17

19 Jan '17

I was recently issue an new laptop from work. Of course, being in a sysadmin position, and giving the latitude to use the tools I deem necessary, I replaced the disk and installed Fedora 25. I felt it was also time to take the plunge with UEFI booting. The Problem =========== After installation, the first boot was successful. After applying updates, boot failed. This was repeatable after a second re-install, and following updates. Symptoms ======== System boots, and goes to a blue and white UI called 'MokManager.efi'. Research revealed this to be a UI for enrolling encryption keys for secure boot. http://www.rodsbooks.com/efi-bootloaders/secureboot.html MOKs—A Machine Owner Key (MOK) is a type of key that a user generates and uses to sign an EFI binary. The point of a MOK is to give users the ability to run locally-compiled kernels, boot loaders not delivered by the distribution maintainer, and so on. Trouble Shooting ================ Firstly, I confirmed that secure boot was disabled in the laptops firmware. Next, I booted a rescue image. Mounted the EFI partition and investigated. mkdir /mnt/boot mount /dev/sda2 /mnt/boot # grub2 boot partition mount /dev/sda1 /mnt/boot/efi # EFI partition We then find the MokManager.efi under the following path in our rescue environment. /mnt/boot/efi/EFI/fedora/MokManager.efi I removed this executable to see what I could discover from the boot process. Upon reboot, I was greeted with message of grub2-x64.efi listed as being corrupt, failing through to MokManager.efi that was now missing, and another optional efi executable that was also missing. Repair ====== fsck.vfat /dev/sda1 - preformed removal of dirtybit> - FATs didn't agreed, selected the first one at random. Going to restore firmware anyways. mkdir /mnt/chroot mount /dev/sda3 /mnt/chroot # root filesystem mount /dev/sda2 /mnt/chroot/boot # grub2 boot partition mount /dev/sda1 /mnt/chroot/boot/efi # EFI partition # Make devices and process table avaliable for j in /dev /dev/pts /sys /proc; do mount -B $j /mnt/chroot$j; done # Make DNS avaliable inside the chroot cp /etc/resolve.conf /mnt/chroot/etc/resolve.conf chroot /mnt/chroot # re-install grub2 EFI executables yum reinstall grub2-efi shim # leave the chroot exit umount /mnt/chroot/boot/efi fsck.vfat /dev/sda1 # just to sanity check that it's still clean. reboot Success ======= Machine booted normally with the latest kernel form updates. Notes ===== 1) I've simplified my device names for convince of conveying the process followed. Adjust appropriately for your circumstances and disk layout. 2) In Fedora 25 is a symylink, /etc/resolv.conf -> /var/run/NetworkManager/resolv.conf, I had to copy this instead, your distro may vary. 3) There was no left over EFI partition from a previous system. This was all done on a blank hard drive. 4) Frankly, I found all of this far simpler to manage then a classical MBR based boot loader. I was able to use standard tools to investigate and repair the boot chain. No special gurb-install commands or dinking with config files. 5) None of this explains why a normal update left the boot partition in a unclean state to being with. But if it happens again, it's an easy enough repair, just a little time consuming. -- Scott Sullivan

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USB-C cable + LG Nexus 5X
by William Park 13 Jan '17

13 Jan '17

Some time ago, I complained about my useless LG Nexus 5X which only has USB-C port. It became slightly more useful this week. I bought - USB-C to USB-A male (Perfekt) - USB-C to USB-A female (Perfekt) cables from Newegg.ca on sale. And, I can now use keyboard and mouse. -- William

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Question
by o1bigtenor 12 Jan '17

12 Jan '17

Greetings Am trying to find (for need in the not to distant future) some of what is normally called 'accounting' software (its really record keeping software but that's a different argument!). What are you using that is, or could be, multi-user and has room for some complexity? (I am presently using 10 digit account numbers to get the granularity I want.) TIA Dee

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Resources I Mentioned Last Night
by Myles Braithwaite 👾 11 Jan '17

11 Jan '17

AdBlocker though DNS /cc @Hecktor * Good for blocking Ads though `/etc/hosts` file <http://someonewhocares.org/hosts/zero/hosts> * Better <https://github.com/StevenBlack/hosts/> Raspberry Pi VPN Gateway Provider /cc @Evan * VPN Provider: <https://www.privateinternetaccess.com/> * Tutorial for making a VPN Gateway: <https://gist.github.com/superjamie/ac55b6d2c080582a3e64> * Onion Pi: <https://learn.adafruit.com/onion-pi/overview> Jobs * Google Interview University: <https://github.com/jwasham/google-interview-university>

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