Ever wondered what was going on with a server or desktop that just wasn’t performing “right”? Sure the load average is a good representation of the overall load as described here, but, how do you track down the actual source of the issue? Try out these five utilities to help you track down any load-related issues with your Linux-based installation.
Yes, that’s right, good ol’ fashioned “top”. If you haven’t already used the top command then you may not have been using Linux that much. Top provides a real-time look at processor time, processes that are using high amounts of memory/CPU and also an overview of physical and swap memory. A preview of top can be seen to the right. Press “1” to show all CPU’s available (if running multiple-core processors or HT-enabled processors).
There are also other top variants out there which can provide more information in the same “top-like” format. Enter htop. Htop has been around for quite some time and has, as far as I know, gone generally unknown around the Linux world. htop provides colorful (who doesn’t like colors?) views of the system state and shows tree views for processes that provide even more detail. A screenshot of the htop interface can be seen on the right. Obtain more information about htop here.
Got disk performance issues? Find out with iostat! iostat is used for monitoring speed, ops/sec and cpu time spent waiting on input/output devices to respond. This command is quite useful when attempting to see what is causing your load averages to spike. If your system has high i/o wait times you may consider purchasing faster disks or tuning the performance of your application to be less disk-intensive. Performance tuning, for instance, of a MySQL database can greatly decrease the amount of disk i/o needed. Adding indexes and re-constructing queries can speed up MySQL systems that have high i/o wait times. Of course, you can always throw hardware at the issue as well. For more information on iostat see this article.
Direct from the vmstat man page: “vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.” The data shown in vmstat is the average since last reboot.
Direct from man page:
r: The number of processes waiting for run time.
b: The number of processes in uninterruptible sleep.
swpd: the amount of virtual memory used.
free: the amount of idle memory.
buff: the amount of memory used as buffers.
cache: the amount of memory used as cache.
inact: the amount of inactive memory. (-a option)
active: the amount of active memory. (-a option)
si: Amount of memory swapped in from disk (/s).
so: Amount of memory swapped to disk (/s).
bi: Blocks received from a block device (blocks/s).
bo: Blocks sent to a block device (blocks/s).
in: The number of interrupts per second, including the clock.
cs: The number of context switches per second.
These are percentages of total CPU time.
us: Time spent running non-kernel code. (user time, including nice time)
sy: Time spent running kernel code. (system time)
id: Time spent idle. Prior to Linux 2.5.41, this includes IO-wait time.
wa: Time spent waiting for IO. Prior to Linux 2.5.41, shown as zero.
Although the ps “process list” command does not show real-time updates it can provide useful information as to why your system may be slow. I typically use the “aux” options that shows enough detail but also adding “ww” to the end of “aux” yeilds good results for long commands. Run “ps aux” and look for multiple processes. This is good for troubleshooting if a process like Apache or Exim have spawned many children and caused the system to slow. Use the “e” flag to show children in a tree format.
"A new server for mid-size companies, the Power 560 Express, is due on Nov. 21. It uses a 3.6Ghz Power6 processor, comes in four-, eight- and 16-node configurations, and packs a hefty 384GB of memory. It’s designed for companies looking to run multiple applications on a virtualized system. It will be offered with Linux, AIX or i."
IBM brings a new line of processors and machines to the market with unreal memory capacities.
Apparently one of Facebook’s founders, Dustin Moskovitz, is proverbially “jumping ship” to start his own Internet company. This quite possibly the best move for him. I’ve known many people who specialize in starting large companies and keep moving. I believe this is the true way to make money when it comes to entrepreneurial endeavors.
Linux Trovalds is the father of Linux. He has been very active in the development of the Linux kernel and recently decided to start a blog. Read his blog here.
It will be interesting if he keeps the blog updated or if he posts a lot at the beginning then tapers off.
So, having avoided the whole blogging thing so far, yesterday Alan DeClerck sent a pointer to his family blog with pictures of the kids friends, and I decided that maybe it’s actually worth having a place for our family too that we can do the same on.
Of course, I’ll need to see what Tove wants to do, but in the meantime, here’s a trial blog.
I just received a letter notifying me that tapes containing data with my information on it were "lost" by BNY Mellon’s archive services vendor. I figured I would make mention of this because it is somewhat technical. I would assume that they are using some sort of encryption routine to protect the data on the tapes. Chances are that these tapes were lost or misfiled. Who knows. The data is most likely unrecoverable but it just goes to show… Even the big boys make mistakes. They do, however, graciously offer 90 days of service from a credit monitoring company. Thanks BNY Mellon!
Here is something odd I found with Google Chrome.
Go to “google.com”
Middle click maps at the top and see the distorted map on the new tab.
What causes this? Google how well did you review your code. I know it’s a beta … but I expect better from Google 🙂 It works fine when visiting the maps site directly or refreshing.
It’s very interesting to see what the web was like then and now. Big sites like FaceBook.com and others have been owned by other companies and have looked very different.
Check out a list of the top five web sites on the Internet (as rated by Alexa.)
Yahoo went through many changes throughout the years.
|October 17, 1996
|Feb 10, 1998
|Jan 22, 2003
Google didn’t really change too much throughout its life thus far. This may be a reason people love Google so much, beside the obvious reasons of course.
|Nov 11, 1998
Strange! The first link was to “google.stanford.edu” and the second to “alpha.google.com”.
|Dec 02, 1998
|Jan 01, 2001
Only 1.3 Billion Pages? Wow 🙂
YouTube has definitely stood the test of time. I wish I would have created a site as popular as this!
|May 16, 2005
|June 30, 2005
|Nov 25, 2005
Nothing too special here. Just them touting about how big a 4GB IPod is!
4. Windows Live (Live.com)
It looks like live.com wasn’t always owned by Microsoft. Check these out!
|Feb 11, 1998
|Jan 02, 2006
|Jan 21, 2007
It looks like the domain “Facebook.com” was originally owned by a company who created “software to manage your world” in 2003. Facebook was originally called “TheFaceBook” back in the day.
|Jun 28, 2003
|Aug 12, 2005
|Oct 31, 2005
Facebook changes in to the site we all know and love.
Images provided by WayBackMachine.
What is a Semaphore? An article I found here is very useful. It says that “Semaphores can be thought of as simple counters that indicate the status of a resource. This counter is a protected variable and cannot be accessed by the user directly.”
This recently came up when the Dell OpenManage storage service would not start on a Linux system. It complained that there were no more Linux semaphores available. Check out the article for more information.
Most of us text message other people and most of us usually have an unlimited text message plan if you do any texting at all. A new way of searching is here. Enter ChaCha. The name came from the Chinese meaning of Search (Cha).
What does it do?
ChaCha allows you to call in or text in a question, any question and receive a useful and helpful text message back (160 characters or less).
How does it work?
A real person is sitting on the other side answering your questions. The beauty of ChaCha is that the question answerers, called guides, get to pick which categories and specify keywords to allow the guide to get questions they enjoy answering. For instance, I can specify that I want to answer questions primarily based around the Internet and computers. Now, most of the questions I receive are primarily about computers and the Internet.
ChaCha pays a guide $0.20/answer. I did the math and you can equate this to around $10-$15 dollars per hour. It’s no job replacement but it really gives you something to do with your free time.
How do I start?
Just text message “242242” (ChaCha spelled out) and you’re set. Start asking questions immediately after receiving the welcome message. You can also call 1-800-2ChaCha and someone will transcribe your voice question to text. You will then receive the answer via SMS.
Ask any question like this: “What’s the cheapest gas between Minot, ND and Kansas City, MO?”
An answer will look like this: “The cheapest gas is $3.55 at XYZ Gas station at 000 S. 110th street in Souix City, SD”
Will it remain free?
I’m not sure about this point. I even asked ChaCha directly and it seems to be free since January, 2008 but may be a subscription service in the future. Any way this is a very useful tool.
Visit www.chacha.com for more information.