• isc-dhcp-server dhcpd how to get longer lease


    You can do a static lease that is tied to the MAC address but what a lot of users prefer is that they come into the office or lab the next day and that their device gets assigned the same IP address (if possible). As we can see in the dhcpd logs that there is threshold that is defaulted as we'll show later. Whatever the threshold is set at, if the lease is younger than the threshold, it will keep the same lease. In other words, if the device goes to sleep or is powered off........
  • Docker Swarm vs Kubernetes Comparison Guide


    A lot of companies are unsure which solution to choose and many may not be aware of Docker Swarm as an alternative to Kubernetes. One thing that many Sysadmins find is that Docker Swarm is simply easier, quicker to setup and maintain by far than Kubernetes.........
  • When is it time to leave your VPS/VDS Cloud Hosting Provider?


    When Is It Time to Leave Your VPS, VDS, and Dedicated Server Provider? Choosing the right hosting solution—be it Virtu........
  • How To Shrink Dynamically Allocated VM QEMU KVM VMware Disk Image File


    Let's say you have a VM file that uses 200G of dynamic space, but really only has 40G in usage. If you add fles and delete, at some point the file will be larger than the current space you are using. Take this image which shows is using 71G of space on the host: The actual space being used inside the image is about 43G as we can see:........
  • Ansible Tutorial - Playbook How To Install From Scratch and Deploy LAMP + Wordpress on Remote Server


    1. Let's work from an environment where we can install Ansible on. If you are using an older version of Linux based on Mint 18 or Ubuntu 16, you may want to get the PPA and get the latest version of Ansible that way: sudo apt install gpg sudo add-apt-repository ppa:ansible/ansible sudo apt update........
  • SSH How To Create Public/Private Key Pair and with a Larger Keysize than 2048 bits


    The problem is that by default ssh-keygen loves to generate an easy to crack 2048 bit key (RSA). Supposedly having a larger keysize helps such as 4096 or 8096 but it is thought to be useless still against Quantum computing. How can I check my existing keysize and type? ssh-keygen -lf /path/to/your/id_rsa.pub The output will be something like below followed by the hash. The first number is the key size and the second part will b........
  • Linux Ubuntu Cannot Print Large Images


    If you are using the default "Image Viewer" aka Xviewer it seems to die on very large resolution files. It seems to understand to scale them but the printer will try to print and then fail. Using "Pix" viewer seems to fix this and causes these larger files to print just fine. ........
  • Linux use growisofs to burn a larger file on a BD-R / Bluray Disc


    growisofs -Z /dev/sr0 critical.tar.gz.gpg Executing 'genisoimage critical.tar.gz.gpg | builtin_dd of=/dev/sr0 obs=32k seek=0' I: -input-charset not specified, using utf-8 (detected in locale settings) File critical.tar.gz.gpg is larger than 4GiB-1. -allow-limited-size was not specified. There is no way do represent this file size. Aborting. :-( write failed: Input/output error #remember to us........
  • qemu-img resize howto


    The Correct Way To Resize In Place qemu-img resize kvmuserwindows2008dcetest.img +1G Image resized. Below is a common mistake that some users make they are trying to specify a new image name but it can be resized in place (just make sure the VMis NOT running and you've backed up the data in case something goes wrong). qemu-img resize kvmuser453111.img kvmuser453111-larger.img +5G New i........
  • Duplicate entry '2147483647' for key 'PRIMARY' MySQL Error Solution


    This usually happens when you are using something like an INT and try to insert a larger valuethan the maximum which is larger than "2147483647" On a practical term I have seen this and been guilty of this error when using scripts like PHPand generating large random numbers: $hash = mt_rand(5,9999999999999); Obviously that many 9's are more digits than the maximum of an INT resulting in that error. Change your code accord........
  • MySQL Maximum INT Size Truncation Issue/Warning


    MySQL will silently truncate a larger INT than capable. Check MySQL's own documentation here: As we can see the maximum size of INT (which is the most commonly used) is 2147483647 A lot of coders make this mistake by using very large values such as 9999999999 but it would actually truncate to 2147483647 which is the maximum size of an INT. This is dangerous beca........
  • ERROR 2006 (HY000) at line 567: MySQL server has gone away


    mysqldump or mysql query of a larger file/table ERROR 2006 (HY000) at line 567: MySQL server has gone away Add this to /etc/my.cnf max_allowed_packet=64M service mysqld restart........
  • ffmpeg how to watermark and concatenate in one command


    If you were in my boat you were frustrated that you had to double encode, eg. one separate encode for watermark and a separate from concat and it's not easy to figure out this with ffmpeg on your own. However it is a nice way to save time! ffmpeg -i file1.mp4 -i file2.mp4 -i file3.mp4 -i watermark.png -filter_complex "[0:v]setpts=PTS-STARTPTS[v0]; [1:v]setpts=PTS-STARTPTS[v1]; [2:v]setpts=PTS-STARTPTS[v2]; [v0][0:a][v1][1:a][v2][2:a]concat=n=3:v=1:a=1[v][aout]; [v][3:........
  • Migrating from Linux Mint 17.2 mdadm RAID array to a new one (because I upgraded to larger drives).


    1.) Replicate the number of partitions in your new drives. gdisk /dev/sda gdisk /dev/sdb I created 3 partitions of the same same size. partition #1: +1G (/boot) partition #2: +60G (swap) partition #3: rest of it (/) #note if you are using GPT/gdisk you need to create separate a partition at least 1MB in size (in my case I would a 4th partition and mark it type ef02).........
  • remove gpt partition linux


    sudo fdisk /dev/sdh WARNING: GPT (GUID Partition Table) detected on '/dev/sdh'! The util fdisk doesn't support GPT. Use GNU Parted. WARNING: The size of this disk is 8.0 TB (8001563221504 bytes). DOS partition table format can not be used on drives for volumes larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID partition table format (GPT). The device presents a l........
  • Uploading Error HTTP error. Wordpress Upload Error Solution


    When you start uploading larger images in Wordpress you have to make sure your maximum attachment size is large enough and that the execution time is not too short: Uploading Error HTTP error. [Thu May 12 16:32:25 2016] [error] [client 10.10.5.2] PHP Fatal error: Maximum execution time of 30 seconds exceeded in /httpdocs/blog/wp-includes/class-wp-image-editor-gd.php on line 182 Solution Edit p........
  • Linksys E2500 DD-WRT Upgrade Instructions and Enabling 5ghz with Tomato Firmware


    1.) Flash directly to this file: http://tomato.groov.pl/download/K26RT-N/build5x-132-EN/Linksys%20E-series/tomato-E2500-NVRAM60K-1.28.RT-N5x-MIPSR2-132-Max.zip *I was never able to get the larger "Mega" file to work, at least not initially so I recommend the file above. To enable 5ghz I had to do the "Clear NVRAM" Option before it was shown. 2.) Or if you don't need 5ghz (most devices do not support it and cannot........
  • libguestfs tools howto guide for mounting partitions and managing virtual machine images


    libguestfs tools howto guide for managing virtual machine images. libguestfs-tools aka guestfs tools has a lot of tools that make this very easy for you. You can easily mount partitons from an image with some of the commands below. To mount a partition #mount the kvmuser102821.img image and the /dev/sda1 partition from it to the local directory "mount" guestmount -a kvmuser102821.img -m /dev/sda1 mount ........
  • bash check that file is not blank/zero bytes in size


    if [ ! -s /path/to/file ]; then echo "file is blank or zero bytes" fi Use -s to check if it's larger than 0 bytes, Ilike to use the ! (not) operator to do this as shown above.........
  • convert PDF to JPG howto in Linux


    Use imagemagick: convert -density 200 file.pdf file.jpg Increase the "density" value to get a higher resolution/larger file an decrease it to go smaller. This is really the quickest and simplest way. Some issues you may have: http://realtechtalk.com/ImageMagick_Convert_PDF_Not_Authorized-2217-article........
  • mdadm: /dev/sdb1 not large enough to join array solution


    mdadm --manage /dev/md1 --add /dev/sdb1 mdadm: metadata format 00.90 unknown, ignored. mdadm: metadata format 00.90 unknown, ignored. mdadm: metadata format 00.90 unknown, ignored. mdadm: /dev/sdb1 not large enough to join array md1's first primary member /dev/sda3 has 57394 cylinders while the /dev/sdb1 has 57393 (1 less cylinder) which is why it won't work. fdisk -l /dev/sda3 Disk /dev/sda3: 47........
  • How To Test If Your Hard Drive Is Good/Signs of dying hard drive


    I like dd, although it only reads it, usually a read test of the entire disk will uncover if your hard drive is bad in some parts. This is a good thing to do at least once a month, a lot of times bizarre program behavior, laginess and crashing/unnmounting problems etc.. are due to a failing disc and SMART won't know it or indicate a problem: We must also remember there's never a guarantee, I've found that ever since we moved to larger and more platters per drive with 1TB drives........
  • RAID 5 doomed in 2009?


    http://www.tomshardware.com/news/RAID-5-Doomed-2009,6525.html I found this article interesting, it basically says that with 2TB hard drives or larger sizes, you are more likely to encounter an unrecoverable read error. But is this just another Y2K doomsday? Don't HDD's have enough advanced hardware ECC error and read recovery to prevent this from happening? I'm almost tempted to build a 3 x........
  • Linux EXT3 16GB-17GB maximum filesize issue solved/how to fix


    I have no idea why but mkfs.ext3 defaults to a patheticlly small blocksize of 1024 bytes/1KB (kilobyte). That means the maximum filesize is ONLY 16GB! With 2KB/2048 bytes you get a 256 GB maximum filesize, and with 4KB/4096 bytes you get 2TB! I finally noticed/paid attention to this after realizing that with rsync and scp that no file larger than 17GB could be transferred. I then realized it must be a file size limit on the partition. Here is what tune2fs tol........
  • Tyan S2735-8M Maximum Hard Drive Limit/Not Working/Doesn't work with 1TB 1000GB hard drives


    Inever saved any of the logs, but basically no matter what OS (Linux)I used, I could not get my 1000GB hard drive to work (Seagate SATA). The BIOS recognizes the drive and fdisk -l shows the hard drive as it should. The tricky thing is that different OS's will give you different results, but don't be fooled. You can't use these larger drives for long. Iwas getting all kinds of seek/IOerrors and also messages that the port could not be read.........
  • Nokia N97 review, feedback and complaints


    I've had an old Blackberry for a few years and I was ready to spend some serious cash on a nice Nokia. I love the idea of the Linux based Symbian S60 OS, so I was looking at phones like the E63, E71 (both are basically the same, at least CPU/screensize although E71 is thinner, has a 3MP camera, has GPS, and has dedicated buttons to adjust the volume). Then Iheard about the N97 and what a revolution it was supposed to be and it was even compared to iPhone. To........
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