Linux Server Security Checklist
- Firewall (apf/csf and bfd)
- Secure tmp partition (noexec)
- rootkit scanning
- PHP hardening
- Apache hardening
- Mod-security
- Shell login notification
troubleshooting linux high cpu utilization
1. us -> User CPU time: The time the CPU has spent running users’
processes that are not niced.
2. sy -> System CPU time: The time the CPU has spent running the
kernel and its processes.
3. ni -> Nice CPU time: The time the CPU has spent running users’
proccess that have been niced.
4. wa -> iowait: Amount of time the CPU has been waiting for I/O to complete.
5. hi -> Hardware IRQ: The amount of time the CPU has been servicing
hardware interrupts.
6. si -> Software Interrupts.: The amount of time the CPU has been
servicing software interrupts.
ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10
I often upgrade Firefox to the latest versions with only conditions: google toolbar, Web Developer extension and Firebug extension supports.
I never ran into problems except with this latest version: 3.0.3
The problem: Websites with self-signed certificate are no longer working. It doesn’t give me the option to add exceptions like it used to be. (websites with exceptions added in previous versions are not effected.)
Tried this:
Go to Tools -> Option menu, select Advanced, on Encription tab click on View Certificates.
Go to Servers tab in Certificate Manager, click on Add Exception
Enter the host (https://localhost) then click on Get Certificate button.
Same problem
After some searching, some are saying to re-set one of Firefox settings in about:config. However it doesn’t work in my case.
I gave it another try in the Certification Manager by use the host name with port number. It worked!
I am glad it worked out and I don’t need to go back to 3.0.2 or wait for fix in the next version.
After a long and delayed waiting, I finally got my hands on this so called “Monster Blackberry”. Yes, it’s the new Blackberry Bold 9000 from Rogers. Unfortunately this one is not mine, it’s my friend’s.
I’ve read so much about its new features. I know what to look into within limited couple hours review time.
Speed:
Yes, it’s lighteng fast. It’s fast everywhere. Open a browser, web page viewing, go back to the home screen, go back to playlist while playing a video in media player and etc.
Screen:
Very impressive hand held device LCD. It’s smaller compare to iphone, PSP but with resolution of 480×320, super bright LCD, I can watch some movies on a Blackberry!
Compare to my Blackberry Curve, Bold supports H264 at resolution 480×272 (only one I tested so far)! My Curve only supports H264@ 16x sth from the official spec. I did try H264 320×240 on Curve, only sound with no image.
Some WinMenc settings:
mencoder.exe “D:\Download\Video\169_diablo3_di_062908_hr.mp4″ -af volnorm -srate 48000 -vf-add scale=480:272,harddup -ofps 30000/1001 -oac faac -faacopts br=128:mpeg=4:object=2 -ovc x264 -ffourcc H264 -x264encopts bitrate=500:level_idc=13:nocabac -o “D:\Download\169_diablo3_di_062908_hr.x264.avi” 2> 2.txt
call “batch\mp4-avc.bat” “D:\Download\169_diablo3_di_062908_hr.x264.avi”
3G wireless:
Fast again! It takes seconds to download google map application. I don’t see the progress bar stops at all.
Things I don’t like:
The earbud comes with the package. I like earbud, however I found it doesn’t work well with the Bold. Even it’s fully plugged into the bold, if I turn the plugged-in earphone, it effects the sound. Sometimes it becomes one channel of sound. It may be caused by bad contact or a defective earbud.
Conclusion:
Before I can get my Bold (in one month or two, financial reasons), I will stick to my trusty Curve.
Hey, I just changed the theme on my Curve to Bold precision theme clone.
some images taken by using an iphone 3G. easy on the image quality
Finally it is working!
It’s an unlocked t-mobile Blackberry 8320 Curve on Rogers network. And it is my second personal Blackberry (owned 8100 before).
Windows live messenger was pre-loaded on this t-mobile’s curve. But it never worked. It failed to connect to the server. The guess was Rogers didn’t have the service books for it yet.
Here’s what I did this time:
Connect your BB with your computer.
Use Internet Explorer, goto wlm.
Follow the steps to load Windows Live Messenger 2.0 onto your blackberry. (You may be prompted to install some activeX control for the loading)
And that’s it!
If it is still not working for you after the above steps, I suggest you take a look at your service book options. It should have something like WLM 2.1 [BBIM], Windows Live [BBIMConfig]. You can try to re-send service books from Rogers BIS.
My Curve is running OS 4.5.0.52.
Ever lose emails on your Blackberry?
The first place I would check is free memory or File Free size of your Blackberry. It happened to me after I updated OS my 8320. It showed less than 3MB after a battery pull.
After some google searches, here is an article of how to maximize free memory on your Blackberry. I removed unwanted .cod, extra theme, voice activated dialing, 83xx media and etc.
To show Blackberry Help Me screen, go to advanced options, then applictions, and press Alt, Cap and H key all together. This is the Help Me screen after wipe and flash the OS:
After enterprise activation, and load the applications I use daily: Google Gmail, Goolge GTalk, Viigo, Mobipocket Reader. And load 2 company testing product. The File Free shows:
I fee much better seeing it’s over 20MB now
This amount of free memory will make 8320 work better with the upcoming highly expected 4.5 OS.
First of all, this post is nowhere near a complete reference for linux memory usage and troubleshooting high memory usage. It only has the steps I’d taken to troubleshoot my own server when it gets overloaded by increased traffic. It happens once a while, and usually I can fix it by tuning some Apache, MySQL and other config setting.
1. using top command
After executing top command, press “Shift” + “>” and look at “RES” column. The RES column is the most reliable indicator of the real memory usage of that process.
2. ps axu –sort:rss
show memory usage sorted by lowest memory usages first.
A general Apache which serves static html page should consume less than 10MB per process.
For heavily serving PHP pages, in my case it uses 18MB-39MB each httpd process.
mysqld has a memory usage of 120MB in my case. I can tell that the query cache settings worked as planned.
ps aux –sort -vsz | head -25
Top memory hogs
uname -a
cat /proc/version
cat /etc/redhat-release
php -v
mysql -V
httpd -v
Well, another update!
I’ve got BL updates on all my websites as well as PR. Traffic of some websites shows a jump today. It’s still too early to see how much the traffic has improved. Let’s wait and see.