Have you ever tried mounting a partition that you exists but you get this error? mount: /mnt: can't read superblock on /dev/sda1. The superblock in this example was bad because the physical disk had corruption and bad blocks/sectors. However, the data was generally accessible and you can always try this trick below (with caution and no warranty). This is specifically for filesystems that place superblocks in multiple locations, which........

Enable "cli" mode equivalent in JunOS cli Configure Mode configure So rather than going to the console on a Cisco switch and typing "enable" and then "conf t", the equivalent in JunOS is "cli" and "configure". How Do You Apply Changes You've Made? You can make all kinds of changes to the switch, but remember they are not........

Do you hate how Centos 7 defaults to allocating most of your valuable space to /home even though it is a production server? Here is a quick guide on how to take back that space live, while online (of course make sure you have backups just in case something goes wrong!): First we will reduce our home dir by 100G: lvreduce -L -100G /dev/mapper/centos-home WARNING: Reducing active and open logical volume to ........

A great way if you have a bunch of drives and mdadm connected and are looking for backups/archives and don't know what is where! for md in `cat /proc/mdstat|grep md[0-99]|awk '{print $1}'`; do mkdir /mnt/$md; mount /dev/$md /mnt/$md; done........

The easiest way to recover or mount an off-line ecryptfs directory is the built-in command from ecryptfs sudo ecryptfs-recover-private It will find your wrapped passphrase and ask for your password and mount it in tmp. Much easier especially when your current active OS is using ecryptfs too. This a fantastic tool when going through old backups.........

In short the solution is just to use vgremove for the actual /dev/mapper device: vgremove /dev/mapper/backups-backuplv box mnt # mdadm --manage /dev/md8 --stop mdadm: Cannot get exclusive access to /dev/md8:Perhaps a running process, mounted filesystem or active volume group? box mnt # lv lvchange lvconvert lvcreate l........

Here is the scenario you or a client have a remote machine that was installed as a standard/default minimal Centos 6.x machine on a single disk with LVM for whatever reason. Often many people do not know how to install it to a RAID array so it is common to have this problem and why reinstall if you don't need to? In some cases on a remote system you can't easily reinstall without physical or KVM access. So in this case you add a second physical or disk or already ha........

CPanel says you can access 98% of the functions through CLI which experienced Unix/Linux admins prefer for simplicity and for scripting.  I've never found CPanel easy to use from the admin panel, it seems everything is hard to find and a simple task becomes a series of hunts. So for people like me here's the list: http://cpanel.net/system-administrators/command-line-scrip........

mysqldump: Couldn't execute 'show create table `general_log`': SHOW command denied to user 'user'@'localhost' for table 'general_log' (1142) One of my clients almost found out the hard way, here is an unlikely situation that happened. 1.) Years ago the client had another VPS to which they backed up a BLOG nightly to an .sql file, what they forgot is that the file also contained all databases (they used the --all-databases option but forgot). So imagi........

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........

Many people aren't aware but recently Dual-Master Replication setups have become increasingly popular. That's because you get similar features and benefits of having a full-blown cluster (difficult to setup and maintain and requires I believe 3 servers just as controllers). With a dual-master you just have a different off-set for the keys and you should be good, but of course there is the chance that at some point replication will halt because of an unexpected or unforseen error........

Install the "Editors" and "Net" groups that will give you rsync, ssh, ssh-keygen and cron. The trickiest thing that I keep forgetting about each time is you have to run "cron-config" which adds the cron service to Windows, and without doing that obviously no cron jobs will be run thus making automatic backups impossible. Warning about rsync/cygwin and using the -a archive switch. It's a good thing I caught this because it doesn't work ri........

One of the purposes of rsync is to backup whole filesystems and archive them but how can you do that properly and restore things to normal if all permissions and ownerships are not preserved from your root filesystem? It's not desirable to have everything running as root, especially not just for an rsync. The Easy rsync preserve permission solution for non-root users sudo is the answer and all you have to do is edit /etc/sudoers At the end o........

This is a great way to use your ftp server space, for example on your web hosting account (althoughI believe many hosts don't allow storage like this), but if you have a VPS/Dedicated Server etc.., this would be perfect. Imagine how easy it is to work with an ftp account that you can just mount as a normal partition or directory in Linux, it would be great for backups etc.. Name curlftpfs - mount a ftp host as a local directory Synopsis........

Not sure what rsync switches/options to use? rsync -PDrphogtl The short version would be: rsync -Pha I think these are really common sense options to use and probaby should be the default. Explanation of rsync switches P = display the progress D = hybrid of --specials and --devices so all special and device files will be copied as well. r = recursive (otherwise rsync won't copy files deeper than........

Before we start I take no responsibility for this, you should have a backup and if you make a mistake during this process you could wipe out all of your data. So backup somewhere else before starting this as a precaution, or make sure it's data you could afford to lose. The RAID 1 Setup (Hardware Wise) I've already setup my 2 x 1TB (Seagate) drives with identical partitions, make sure your new hard drive (the empty one) is setup like your curr........

The folder I was trying to archive is about 72GB, but much like rsync at about 17GB it chokes because of the filesize. What's with so many common and essential Linux tools having such limitations? I guess it is likely that the authors never wrote their code with the idea that files would be so large but it's still very annoying. It's important to stay on top of these limitations on production servers because I didn't realize what happened until I checked the file with "........

rsync bash script [code:1:722d8a25c1]#!/bin/bash # config --------------------------------- # two methods # from = receive data from another server # to = send data to another server rsync_method=from rsync_ip='192.168.5.18' local_dir='/home/backupguy/backups' remote_dir='/home/backup' free_space_bin='/home/backups/freediskspace.sh' # config end ------------------------------ if [ '$rsync_me........

Create Table with structure of another existing tableOk, this has many valid uses such as if you need to create backups or the ability to undo changes, you would want to create new tables with the same structure as another. Here is how you do it. [i:7ed9581493] Also remember Indexes such as PRIMARY KEYS [b:7ed9581493]will not be preserved[/b:7ed9581493] so you will have to readd them manually.[/i:7ed9581493] [code:1:7ed9581493]CREATE TABLE NewName AS SEL........

Bash Script Infohttp://www.faqs.org/docs/Linux-HOWTO/Bash-Prog-Intro-HOWTO.html#ss10.5 http://www.scit.wlv.ac.uk/~jphb/spos/notes/shell/shell5.html http://quong.best.vwh.net/shellin20/#LtohTOCentry-41 http://www.cactus.org/~dak/shellscript.html http://db.ilug-bom.org.in/Documentation/abs-guide/ http://pegasus.rutgers.edu/~elflord/unix/bash-tute.html http://heather.cs.ucdavis.edu/~matloff/UnixAndC/Unix/CShellII.html Since bash i........

How do you copy a DVDHow do you copy a DVDI'm assuming you mean how you can backup your DVD titles? If you are talking movies, you should use AnyDVD and CloneDVD, they are excellent tools for backups. For data CD's, Nero has a DVD-Copy option and that should work well for most purposes. Hope that helps. :D........

I've gotten this error enough to bother posting about it, because I've come across so many servers where this happens, so what could "Error 28" possibly mean? Is your database corrupt, or is this a sign of a RAID failure/corruption or even worse, bad blocks on a clients system who has no RAID and never took backups? No, check your free blocks, it simply means you have no space. This was the result of a script that was overzealous and backed up the entire database........