At $WORK, we currently use cfengine 2 to manage on the order of 300 systems. It works, it does most things we want. We use the Singlecopy Nirvana "pattern" to distribute configuration files of all types, have copious shellcommands, and even a few editfiles. In general, it does what I need, but not necessarily the way I want. The general structure of our cfengine configurations is (for the most part) unchanged since I implemented it ~4 years ago. We've done the necessary things to support new OS's, new architectures, what have you, but that's about it.

Like many of you, I like to have some of the latest technology at my fingertips. Specifically, I'm talking about my workstation. No, while I don't have über-fast sexy hardware, I like to at least have the latest OS flavor(s) installed so I can play with new features.

The other day I decided it was "time" for Fedora 12. Time to play with ext4.

Before I begin, a small word about my prior setup:

disk 1: Windows XP, NTFS partition. Old, crusty, not used anymore, as I have XP in a VM now.
disk 2: Fedora 11, Linux LVM partition. No real data of value, but it does house my XP vm.

Coming from a rather hardcore X11 background (mm, X10 with b/w displays), my adjustment to Life With Mac has been made much easier recently with the installation of a utility called Zooom/2. [2] Although it can't (yet) bind my X11 finger-macro of alt+mouse2+move to window-move, it can bind it to any combination of modifier keys, defaulting to command+shift+move. window-resize is bound to option+shift+move.

Along with autoraise and focus-follows-mouse capabilities, this utility has already earned a permanent spot in my essential Mac folder.

A small dampener: There's still a few bugs or design interactions lurking about, especially when combining autoraise, focus-follows-mouse and Spaces. Focus can shift bizarrely to another space when least expected, and some applications get upset about abrupt resizes and can abort. The developer has been quick to respond to my bugs reports thou, so I currently have hopes that these issues can be addressed.

It's Friday afternoon, about 2pm. I have a console/management server that is having some difficulties with Splunk 4. Whether or not the RHEL version (4.8) is the cause-- I have finally decided it's time to upgrade to RHEL current (5.4). That way I can at least eliminate the OS as the cause of the issues I'm seeing, and so on. And, being Friday afternoon, it's quiet.

What could possibly go wrong?

I checked my ISO directories for the particular RHEL image I need (ver 5.4, x86). Yep! I've used it a lot on several VM's, but haven't needed to upgrade anything that's actual hardware yet. No problem, a few minutes later I had a hot & crispy DVD in my hand with 5.4 freshly burned on it. Off to the data center.

As our technology grows, along with pieces-parts from multiple vendors, so does our job as the technical equivalent of Dr. House. In many ways, what we do as sysadmins is very very similar to that popular TV show (which, by the way, is one of my favorites - his crankiness is something I intend to aspire to...). On the TV show, House guesstimates the problem with the patient of the week-- administers various types of remedies (all of which fail), the patient nearly dies, and at the last second- in a brilliant flash of insight, he figures it out.

Today is a day like many other-- I'm going through the above process. Software: Sun Storedge Enterprise Backup. Backup server: Sun X4500 ("thumper"). Tape Drive: Sun Storedge SL24 tape loader.

We are migrating from our old mail server to a new one with a completely different internal structure and many new features. I am using imapsync to migrate the data over (slow, but it works well). Before we do the last sync, my boss asked me to figure out a way to run the servers side by side so we could have the early adopters try the new mail server. The kicker is that both servers are set up to serve the same domain and we need to be able to have the early adopters get to their mail from either server.

This solution works for us, but I am not sure if this is the best solution and would love to hear your ideas.

Have you ever had the need to allow web access to files on a samba or windows fileserver and really did not want to deal with setting up a VPN for the users (some of whom need access to just see a single file) or keep track of permissions on the file server and it the apache config file (e.g. htaccess for directory level access). The answer I found was IntegraTUM WebDisk (http://www.simple-groupware.de/cms/WebDisk/IntegraTUMWebDisk). It is a java application that takes a user name and password and uses that to make a smb connection with a samba or windows file server. Because it is making an smb connection, it respects all the file server permissions just like if the person was using a file browser on their linux, windows, or mac client so you only have to maintain permissions on the file server.

I was asked recently to find a low cost setup for a small software development company (about 30 people) for their infrastructure that had growth potential. I came up with the following:

- One server running Open-E DSS software SAN/NAS: This holds 12 1TB disks in a raid 10 mirror and shares out the disks via iscsi, smb, and nfs (I am not using the other protocols available such as AFP, FTP...). It is certified for VMware. They use it for home directories and as an iscsi SAN for ESXi.

- Two servers running ESXi software attached via iscsi to the SAN.

along with a UPS, rack, switch, and firewall.

A while back I wrote about using Apache as a dynamic reverse proxy. Anyone who has done even minimal research into web servers knows that Apache is the swiss army knife. It trys to be everything for everyone, and like a swiss army knife may not be as good as a more refined too at least as far as efficiency is concerned.Read the full article Transparent dynamic reverse proxy with nginx at -->

System performance analytics seems to be a frequent question on forums and mailing lists. Finding out why something is slow is generally nontrivial as there are many factors to consider. I have found the sysstat package to be an invaluable tool when looking at system performance. Specifically the command sar gives a wealth of information.

Read the full post Analyzing linux system performance and finding bottle necks