Proving the Network is Not the Problem With iperf – Packet Life

Sysadmin, Tutorial, Unix
Proving the Network is Not the Problem With iperf - Packet Life: "When an application fails to perform as expected, the network is often the first thing blamed. I suppose this is because end users typically view the network as the sole limiting factor with regard to throughput, unaware of the intricacies of application, database, and storage performance. For some reason, the burden of proof always seems to fall onto networkers to demonstrate that the network is not at fault before troubleshooting can begin elsewhere. This article demonstrates how to simulate user traffic between two given points on a network and measure the achievable throughput." (Via.)
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Copying large number of files between two Unix/Linux/OSX Servers

CLI, Linux, OSX, osx Server, Redhat, rsync, ssh, SuSE, Sysadmin, Tip, Ubuntu, Unix
Here are some quick tip(s) for copying a ton of files between unixy machines really fast. You're probably thinking "why not use rsync?"…..well rsync can be miserably slow if your source or destination cpu is underpowered. You can always do a rsync after these commands to make 100% certain that everything checks out, but try using one of these methods for the initial copy: One way of doing it is tar -c /path/to/dir | ssh user@remote_server 'tar -xpvf - -C /absolute/path/to/remotedir' You'll be prompted for the remote servers password or you can use the private key of the remote server using the -i switch in the ssh command. This has the side benefit of preserving permissions. An alternate version of this command can also be used to locally move folder…
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OSX Server: Could not setup Mach task special port 9

Apple, Macintosh, osx Server, Sysadmin, Tip[1] (0x10f860.cron[43786]): Could not setup Mach task special port 9: (os/kern) no access If you're seeing this warning/error in your OSX Server log files, it is more than likely caused by cron running jobs for mailman subsystem. Even if the Mail process is disabled in Server Admin, OSX will try to run these cron jobs. The way around this (only do this if you're NOT running mail server or mailman mailing list manager on your box) is to comment out all lines in /usr/lib/cron/tabs/_mailman file (insert a # character at the beginning of each line that doesn't have it). This fixed the problem for me.....hopefully it will also work for you :-).
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MySQL Replication howto for Snow Leopard…

Apple, Macintosh, mysql, osx Server, Sysadmin, Tip
We recently upgraded our servers from old XServe G5's running Tiger to the latest greatest running Snow Leopard. In this small howto I will deal with the procedure I followed to setup mysql master-slave replication between two new servers. I start out with two (master, slave) empty DB's, setup the replication and then import my data from a third server (my old G5 X-Serve). Of course like anything else I will try to show you how to get out of -- what I like to call -- Steve Jobs Hell Holes :-). There are other ways of doing this procedure, for more info check out this page. - First things first....the magic command that stops mysql server from command line, just in case you screw something up and need to…
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MySQL: Transfering users and priviledges to a new server….

CLI, mysql, Sysadmin, Tip
So this was a great big mystery this morning. How the heck do you transfer the users and their privileges out of a old mysql server and "import" them into a new server. We recently upgraded from OSX 10.4.11 to a couple of spanking new Snow Leopard servers and during the mysql export/import cycle this issue came up. Well the simple answer is.....DON'T USE mysqldump on your mysql DB (you know the default DB that stores all your users and privileges. It's a bad idea and will probably do more harm than good. Instead use the following procedure: 1) On your old server (the one that has your data/users/tables on it) issue the following command (replace YOUR dbadmin/root username and  password in the 2 appropriate places: mysql -B -N --user=admin…
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When SysAdmins Ruled The Earth…

Sysadmin, Technology
Just found this on Cory Doctrow's blog.....When SysAdmins Ruled The Earth....It's a great read/listen, specially if you're a current/former SysAdmin.Here are the different parts read during his podcast over a couple of sessions:Part 1Part 2Part 3Part 4Part 5Part 6If you like to read it yourself here is the entire story. This is great stuff........They even kill the CN Tower......Now you can't ask for more than that people.
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Four little Security tools you should install in Ubuntu

Linux, Sysadmin, Tricks, Ubuntu
These should probably also be installed under other linux distros (might already be). But for the sake of completeness here they are:1) denyhosts: great little package that's already 98% configured after apt-get install process. It runs as a daemon and monitors /var/log/auth.log file for unsuccessful ssh logins and takes measures to ban the originating IP in /etc/hosts.deny. The cool part is that it does not need access to firewall or anything. Config file is /etc/denyhosts.conf and is pretty self explanatory. Ubuntu package is called "denyhosts" and needs python to work.2) chkrootkit: another little gem that you install via apt-get install process. Ubuntu package is called "chkrootkit". After install do "man chkrootkit" for more info, but the gist of it is that when run from command line it uses it's own…
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Changing DNS hostname on OSX Server

Apple, CLI, Macintosh, osx Server, Sysadmin
If you ever need to check the DNS hostname under OSX server here is the command:$ sudo changeip -checkhostnameIf you need to change it (ie: after a DNS table change) use the following command (for OD sites):changeip /LDAPv3/ new.example.comchangeip also has a lot of other uses (ie: if you change the ip address of your machine you can use changeip to change the setting in the directory as well). Have a look at the man pages for more info.If you're having trouble kerberizing your Open Directory under OSX server then you are also most likely having hostname problems. Run the first command to check the hostname information and make sure "Current Hostname" and "DNS Hostname" in it's output match. If they don't use the second command to…
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