• chroot in Linux Howto Simple and Easy Guide


    chroot which stands for change root allows you to virtually operate in another operating system even though you haven't booted it. It is commonly used to deploy new distros, applications and to fix a broken Linux/Unix install or prep a new system image without having to physically boot the drive or disk. So in this example let's say we have a drive that has a Linux OS installed on /dev/sdb1 and we have mounted this partition on /mnt/sdb1 The key point is to edit the &quo........
  • How Does Cisco CUCM (Cisco Unified Communication Manager) Work?


    Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments. Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........
  • DRBD Slow Performance - 99.99 % [jbd2/drbd0-8] highiowait solution


    Tired of checking iotop and seeing that your drbd partition is using 99.99% of io all the time and finding your drbd device performs slow in general? This is especially an issue in versions of DRBD in the 8.3 tree in particular one documented case is on "8.3.13" but it likely applies to other devices. The symptoms are that resyncing is fine and normal but any reasonable amount of activity is very slow and lagged and creates a high server load and con........
  • sed how to avoid escaping


    sed gets to be a pain and a real mess and is hard to read and understand when you have to escape things like / etc. Idid not realize until recently that you don't need to use / as a separator, you can use virtually any non letter or number character. Eg we have used # as the separator to avoid having to escape the forward slashes and in this way the command is plain, easy to understand, edit and saves time/hassle without the need for escaping. sed -i s#http........
  • status: { DRDY ERR } error: { ICRC ABRT } failed command: WRITE FPDMA QUEUED MCP55 Linux Errors


    [ 2868.041375] ata1: EH in SWNCQ mode,QC:qc_active 0x40 sactive 0x40 [ 2868.041554] ata1: SWNCQ:qc_active 0x40 defer_bits 0x0 last_issue_tag 0x6 [ 2868.041556] dhfis 0x40 dmafis 0x40 sdbfis 0x20 [ 2868.041874] ata1: ATA_REG 0x41 ERR_REG 0x84 [ 2868.042013] ata1: tag : dhfis dmafis sdbfis sactive [ 2868.042163] ata1: tag 0x6: 1 1 0 1 [ 2868.042301] ata1.00: exception Emask 0x1 SAct 0x40 SErr 0x400000 action 0x6 frozen [........
  • VPN Account Buyers Guide and General Info


    What does VPN stand for? VPN stands for Virtual Private Network and is a secure way of connecting networks and devices. In the context we're talking about it will usually be a client-server solution and not connecting whole networks or businesses. The assumption is that most people reading this are trying to secure their internet connection, privacy and hide or change their IPaddress. Why use a VPN? There are many........
  • Kernel/make compilation time and how to improve compile times/compile the Linux kernel faster without hardware upgrades


    I thought only a faster CPUand SSDwould help but I already have a Quad-Core CPU and it wasn't being maxed out. The actual tests were performed on an AMD-V enabled 128MB dual core VMWare container though. There is a flag that can be passed to make in order to start multiple threads, by specifying 4 threads I was able to reduce the whole kernel compilation time from scratch by about 50%! (65minutes vs 31minutes!). *Yes I did do a make clean before each co........
  • Buffer I/O error on device fd0, logical block 0


    Virtually no system has a floppy disk drive anymore but you will often find your Linux distribution insists that you do or should have one :) The solution is to remove the floppy module and prevent it from loading on the next reboot. rmmod floppy Centos/RHEL echo "blacklist floppy">> /etc/modprobe.d/blacklist Debian/Ubuntu sudo echo "blackli........
  • Geoip and Geocity Packages


    The "Geoip" package is available on virtually all Linux and Unix like systems and is very handy in looking an IP address' corresponding country. The homepage of the maintainers is here. They also have a package called "Geocity" which can be downloaded from their site, it is still free and gives you a close indication of the city the visitor is from. You can........
  • iPhone Enable Tethering Manually Update ipcc Carrier Settings/Update via SSH


    Everyone says there is a "manual" way of doing it and then they tell you to use iTunes, but if you're like me, you're travelling on business in a foreign country and your laptop does not have iTunes and you don't have a way of getting it and/or don't want it. For this example I'm using the provider "du" in Dubai, UAE (United Arab Emirates) but this method works for virtually all providers. The requirements in this case to truly "manually update........
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