/ - rtt - IT Resource

  • systemd management using systemctl and journalctl to check systemd logs


    systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system. The key commands or arguments you will use with systemctl are the following: Unit Commands:   list-units [PATTERN...]         List loaded units &nbs........
  • l2tp ipsec VPN Error Sep 12 18:16:25 vps pluto[7299]: ERROR: asynchronous network error report on eth0 (sport=500) for message to 192.5.6.2 port 20640, complainant 192.5.6.2: Connection refused [errno 111, origin ICMP type 3 code 3 (not authenticated


    Sep 12 18:16:25 vps pluto[7299]: ERROR: asynchronous network error report on eth0 (sport=500) for message to 192.5.6.2 port 20640, complainant 192.5.6.2: Connection refused [errno 111, origin ICMP type 3 code 3 (not authenticated)] Some say changing the "leftprotoport=17/%any" will fix this but I have not found this to be the case. Essentially it means at least one end is blocking the ipsec packets.  Sometimes the %any allows an alt........
  • ffmpeg trouble concatenating similar but different files


    When things go wrong your video is basically unplayable or the first video plays fine and then freezes when moving on to the next.  Generally if both videos weren't produced with the exact 100% same settings you will have issues.  You can try the basic concat but it often won't work right. Solution for me: My example uses 3 videos in total so "n=3"  and a=1 to include audio. ffmpeg -threads 12  -i file1.mp4 -........
  • Linux Mint Install Netboot PXE Guide Howto


    *Update so this doesn't work it must be something to do with the path of nfs or something else but the installer fails with "Installer crashed" at the end whereas with the CD/USB it works. This assumes you've already installed and configured a separate PXE/DHCP server somewhere else and your /tftpboot directory is setup. This is for Linux Mint 18.1 but generally applies to most versions although you may have tro change things like "casper"........
  • Dell CS24,FS12 NV5 and NV7 1U Server Information & Parts


      Motherboard: Gigabyte GA-3CESL: http://b2b.gigabyte.com/products/product-page.aspx?pid=2658#dl Dell Part Numbers for the motherboard:  R1232 R1232L R2232S SERVER MOTHERBOARD GENUINE 408P9 CN-0408P9 GA-3CESL Manual Download here RAM Slots: 16 (8 controlled by each CPU) RAM Type: DDR2 ECC 5300P........
  • Failed to load VMMR0.r0 (VERR_SUPLIB_OWNER_NOT_ROOT)


    Failed to load VMMR0.r0 (VERR_SUPLIB_OWNER_NOT_ROOT)   In most cases the error above is useful, it generally means /usr or /usb/lib or /usr/lib/virtualbox is not owned by root and this is the cause of the error. Solution sudo chown root.root /usr/lib........
  • MySQL Error : Table 'datastore' is read only Error Number : 1036 solution


    This happens because of a permissions or ownership issue. Generally /var/lib/mysql should be all owned by mysql.mysql (check that). To fix it use chown -R mysql.mysql /var/lib/mysql Also make sure the files are at least readable and writable by mysql (eg. 700).........
  • Bad Hard Drive Slows Down Computer


    Here's a proven example of what a bad hard drive can do, it was technically functioning OK in a RAID array but the system became extremely low and the load become high and IOWAIT was even higher and I always thought it was a bad application.  The truth is that this failing 1TB Hitachi has slowly gotten worse and caused huge slowdowns, (eg. 100% load on Thunderbird waiting for e-mails to load etc..).  After swapping it out, tabs change instantly, emails are not lagged, and........
  • Samsung Galaxy Note Upgrade to ICS 4.0 microSDHC card not detected/dataloss after upgrading - possible solutions


    I backed up everything in the /mnt/sd_card directory thinking that some dataloss could occur for some reason but purposely left my microSDHC unbacked up thinking that "it won't touch that since it's external" and Samsung's and other manufacturers website even say this (that it won't be affected and not to worry etc). Apparently I was wrong, my microSD was "undetected" and asked to be formatted after the upgrade (there goes 3-months worth of family photos).  No........
  • The Importance of a High Quality Power Supply/Power Supplies To Prevent Overheating/System Crash/Hardware Damage


    For years I've always built cheap systems believing that there is little difference in more expensive components when it comes to reliability and quality, I generally believe this still except for Power Supplies. I've always bought cheap cases with nice sounding 350-550W stock/cheap/crap power supplies and haven't had any issues for the most part until recently. One such case is an NGEAR case with a 550W Optimax power supply, I always read that these supplies don't produce the........
  • What's Needed To Fix Linux


    I really am a Linux fan but my comments here may not show it.  Although I'm quite familiar with Linux CLI to administer servers, I find Linux GUI OS's like Ubuntu at times very clunky. This is partially because there's no such thing as a "self-made" Linux from scratch where the UI was designed by a single team.  Linux is made up of several different projects that are generally completely separate and this lack of integratiion is a key issue that makes things f........
  • VirtualBox Convert Import/Boot .vmdk VMWare Hard Disk/Drive Image Won't Work


    I wanted to Import/Use a .vmdk hard disk image file from VMWare.  Generally you can just "point" VirtualBox to it and use it and it will work but I found an exception. One of my Centos 4.4 x64 images wouldn't boot.  I had two copies, an older one and the newer one.  The older one booted as normal (once I changed the VirtualBox driver to IDE from SATA).  The newer one stopped at the "GRUB loading" message no matter what I tried. As far as........
  • Ubuntu 10.04 Linux is still not ready for the Desktop world


    I am a huge fan of Linux and the idea of OpenSource but I've said it many times, there are still hurdles in today in 2010 for Linux as a Desktop.  Linux is still intended for servers at its very core.  This can be changed succesfully though, as Apple has shown us with Mac OS X based on FreeBSD. Half of the issue is lack of driver support and the other half is the Linux Kernel and Window Manages, KDE and GNome still both don't cut it (but they're getting closer). I'll........
  • Why is RAM pricing so expensive volatile lately?


    I'm guessing RAM manufacturers forgot they're not the oil/gas companies and are playing games.  It was just a year ago when I was buying 2GB sticks as low as $20 CAD!  Now the average price is $50 CAD. What happened to Moore's law when it comes to pricing for RAM?  Every other piece of hardware generally has been coming down without exception.  ........
  • CDR Manufacturers - Why is so much media bad?


    CDR Manufacturers - Why is so much media bad?I have searched for good media and tried many kinds for years. I guess I'll try to summarize my findings and conclusions. Dye is irrelevant, dye of any color can be good or bad, it more likely depends on the manufacturer. Speaking of manufacturers, the name at the top of the disc means nothing. For example, Memorex along with any other 'brand' is actually always made by another manufaturer including CMC Mag........
  • Other Security Web Sites


    Other Security Web SitesSeveral websites actively track security issues. This list provides you with the major providers of security information on the Web. Many of these organizations also provide newsletters and mailings to announce changes or security threats: Center for Education and Research in Information Assurance and Security (CERIAS) CERIAS is an industry-sponsored center at Purdue University that is focused on technology and relate........
  • Adventures in pre-paid SIM Cards and data GPRS/Edge/3G in China with China Mobile in Shenzhen, Guangzhou, Shanghai, Beijing and other cities


    This really is a difficult and confusing process for non-Mandarin speakers, but here's what I've done and learned so far: You can purchase an "M-Zone" China Mobile pre-paid SIM Card from almost anywhere but I tried to purchase mine from Suning (a large electronics dealer) hoping they would be able to help me or answer my questions but my plan didn't work out at all.  At Suning once I found someone who spoke some English they gave me the 55 RMB M-Zone China Mobile P........
  • Clustered/Distributed Network Filesystems, Which Ones live up to the hype?


    I've tried to find a good sensible solution to cluster with and each technology has it's pros and cons and there is no perfect solution and I've found a lot of "exaggerations" in the applications, benefits and performance of these different filesystems. DRBD I first started off with DRBD and I have to say it does live up to the hype, is quite reliable (although it can be annoying to match up the kernel module and user applications since they must match and whe........
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