In one of my previous posts: MySQL backups, I talked about using a script for automating backups. I show that we can use gzip to compress backup file to compress and save. Since then, our backup file has been growing meg or two a day which is causing our backup files to get [...]

Its that time of the year again when time changes and we have to make sure our servers are using the right zone with right time. Out of many servers I admin, I found 3 servers which had wrong time displaying. All of them had one thing in common, Fedora Core 4. So I fixed it by doing the folowing.

mv /etc/localtime /etc/localtime.old

ln -s /usr/share/zoneinfo/PST8PDT /etc/localtime

We were having issues with mysql threads where they would be in sleep mode and wouldn’t die off for long time. At the same time we started having issues with our servers where the load will spike and eventually server will come to halt unless we killed all the apache processes and restarted apache [...]

Now since I reinstalled Vista 32bit version and its up and running, lets go through what works what don’t.

1. Daemon Tools (check)
2. Microsoft Office (check)
3. Trillian (check)
4. VMWare Server (CHECK!)
5. Diskeeper 10 (Nope, apparently I have to go download an update for Vista, postponed)

Ok now the fun part starts. How to get everything working the way I want to.

I need to start my Fedora virtual machine so I can get some development/testing done. And a wall I hit. It says that I don’t have permissions to open the file. I am logged in as a user which belongs to Administrators group. So why do I not have permission? Well let me copy it to desktop and see if that works. Voila! it does! Ok.. I will let this one go since I have already wasted my whole weekend getting Vista going.

OK.. so lets change my hosts file so I can point some domain names to …

While looking through my new Vista, I found out that my cpu is 64bit capable! I was like.. OMFG hell yeah! I whipped out the 64bit Vista DVD and nuked all my hard work of setting up software without even giving it a second thought… About 20 mins later, I was back in my new found love, except this time I dove right into installing software. One by one, I get basic stuff installed in following order:

1. daemon tools (went out and got the upgraded vista version) no problems
2. Microsoft Office 2007 ultimate, uh.. thank god no problems there
3. McAfee VirusScan, ofcourse problems.. knew that from 32 bit version but what the hell.. was worth a try
4. Trillian - another no problem
5. VMWare Server………………………………………….PROBLEMS! Sigh.. they don’t support 64bit Vista. Who would’ve known? They support installing 64bit version as virtual machines but then why they don’t …

There I was sitting and working and minding my own business when I heard bunch of noise outside of my office. So I took my headphones off to tune in to the conversation. One of the developers has gone out and bought Windows Vista Ultimate edition and was talking about installing it and trying it out. I have always tried out all of the Windows flavors since 3.1 as soon as they came out and even did beta runs for NT 4, XP, 2000, 2003 and even Vista. But for some reason after installing and running beta 2 of Windows Vista, I wasn’t very impressed. But when they were talking about installing Vista, I myself got curious to find out how good/bad is the released version. So I went and got myself a copy of Vista Ultimate as well.

I didn’t want to destroy my laptop so I decided to install it on my old computer. The specs of that computer are:

Intel Pentium 3.2 with hyperthreading, 2 gig ram, Nvidia GeForce Ultra with Dual DVI

…

I have been asked numerous times what does “load average” means in top. If you don’t know what top is and you have access to linux machine, go type top now and see what it shows.

load average: 2.05, 2.17, 1.93

Quick answer is: first number (2.05) is 1 minute avg, second number (2.17) is 5 minute avg, third number (1.93) is 15 min avg. Generally system admins look at these #’s to see how is their server is doing. But now you wonder, if this is the #’s you look at, why is there cpu %? Isn’t that computer load also? Ofcourse it is. BUT, meaning of cpu % shown in [ Cpu(s): 14.2% us, 1.7% sy, 0.0% ni, 80.7% id, 3.1% wa, 0.0% hi, 0.3% si, 0.0% st ] actually just means how much % of time was spent doing stuff on cpu. On the other hand, load average takes other things such as how much cpu’s were being used and how many process had to wait for their turn to use cpu, etc. Thats why sometimes you will see high % for Cpu …

MySQL backups are essential to running a site with MySQL backend. Generally you can get away with doing nightly backups but on our site, due to couple issues we had in past, we are forced to do hourly backups of our db. Intially I was doing backup by using: mysqldump dbname > weekdayHour.dbname.sql hourly. [...]

Problem:

One of the sites I maintain has been getting more and more traffic everyday. A very good thing for the site, not so good for the solo server which is serving those pages. The site is VERY dynamic with LAMP setup. We only have one server serving our web pages to our users. Since its a dynamic site with PHP and MySQL, it has a lot of load during peak times. Average load time of a page is between 1-2 secs during normal usage, 2-5 secs under average to heavy load.

During heavy load, we started to see our mysql stop responding to requests which is a big concern for us since we don’t show content if there is no db connection. We had to come with a solution, fast, to prevent this issue from appearing.

Solution:

So here are couple things I ended up doing on the server side to reduce load on this server without having to do much code change.

• We have couple other …

We used to use Google mini to index our site to serve search results to our users. It worked great for a while until sometime back it just stopped indexing. It would get a fatal error and stop index after couple urls. It was also not so kind about sending me an email to let me know that it has stopped indexing. It was still serving pages which were indexed prior to this so we didn?t realize it wasn?t indexing new content.

And than one day we logged in to the admin console to see whats going on with it and found out it wasn?t indexing. I checked the logs and found out that it was stopping due too too many 4xx errors. After looking at logs on our web server I found out that it was stopping because Apache was giving back 406 response code which is described at w3.org as:

The resource identified by the request is only capable of generating response entities which have content characteristics not acceptable according to the accept …