Many people are confused between the compression and deduplication because they are so similar. Both of them are designed to reduce the size of the data being stored in the storage. Let me explain the difference between them in simple English. 1. This is how your data looks like originally (Assuming only one unique file): 2. This is how your data look like after being stored in a ZFS pool with compression enabled. 3. This is how your...

After I updated the Apache to 2.2.22 for my FreeBSD box today, I got a problem: #apachectl stop #apachectl start [warn] (2)No such file or directory: Failed to enable the 'dataready' Accept Filter If you search for Failed to enable the ‘dataready’ Accept Filter on Google, you probably will find a lot of posts about this solution, like the following: #kldload accf_http Or include the following in the boot loader...

Today, I found that one of my PHP scripts stop working. After some investigations, I found that it was the function, imagecreatefrompng, which caused the problem. Interestingly, other similar functions such as imagecreatefromgif and imagecreatefromjpeg were completely working fine. The program stopped working when calling imagecreatefrompng only. Initially, I thought the problem was coming from the PHP side. Therefore, I tried to get...

Upgrading FreeBSD is very easy. Thanks for the simple architecture and the disconnection between the kernel and the applications (ports), it won’t take too long to upgrade the system (15 to 45 mins). Here is a quick tutorial to show you how to do it. Notice that this tutorial only works for i386 or amd64. For other CPU architectures such as Sparc, you will either reinstall the whole thing or rebuild the whole world (i.e., make...

When you check the ZFS status, you may find the following error message: One or more devices has experienced an error resulting in data corruption. Applications may be affected.. There can be million reasons to cause this error message showing up. Of course, 99% of them are caused by hardware failure, such as bad hard drives, broken cables, defective motherboard, or even bad memory. In this article, I am assuming that you already...

Imagine that you set up a computer at a public location, such as cafe, library, or computer lab in your school, so that any one can use your computer. Most of the time, users mainly use the web browsers for surfing the web, checking the email, or updating the status on social websites etc. At the mean time, they may download some files on your computer, generating a lot of browsing history in your web browsers, accidentally saving their...

A new version of PHP (5.3.9) was available in FreeBSD today. Since it contained a lot of security fixes and enhancements, I decided to give it a try. After testing the new PHP in couple test servers, I think it is ready to upgrade the PHP on the production server. Oh well, I didn’t expect that I needed to spend my whole lunch break to trouble-shoot this problem. So here is what I did: # cd /usr/ports/lang/php5 # make install ===> ...

Recently, I built a FreeBSD server with ZFS file system using six 2TB harddisks. If you like to learn what I have done or understand more about ZFS, you can read the story here: ZFS+USB: Building a Super Large Server Using USB Memory, CF Card and SD Card.. Many people found a problem on their ZFS system. The speed is slow! It is slow to read or write files to the system. In this article, I am going to show you some tips on improving the...

Few days ago, I found that the CPU fan of this server (i.e., icesquare.com) was having some troubles. It was spinning slowly and making some weird noise. After opening the computer case and had a brief investigation, I found that the fan needed to be replaced. Unlike the computer case fan, CPU fan works with CPU socket. Given that there are so many different sockets available, it is not likely that the local stores have each in stock. In...

When I tried to upgrade my FreeBSD system today, I received a last minute Christmas gift from the FreeBSD team. #sudo freebsd-update fetch Looking up update.FreeBSD.org mirrors... 4 mirrors found. Fetching metadata signature for 8.2-RELEASE from update4.FreeBSD.org... done. Fetching metadata index... done. Inspecting system... done. Preparing to download files... done. The following files will be added as part of updating to...