Changing or Updating the time zone in Ubuntu Server

  There are quite a few reasons you may find that you need to change your time zone – for example, if you’re using a pre-made image for a virtual machine you may find that the default timezone is not set to your country. You can change the time manually, though there is a quick and easy way:  
sudo dpkg-reconfigure tzdata  
This reconfigures the tzdata (timezone data) package and runs you through a series of prompts asking which country/city you live in, and updates the time accordingly.   You can check the current system time with:  
date
  to verify that it worked!

Ubuntu Server: How to change to the root user

  Some guides tell you to enter “su” on Unix systems to get superuser permissions; in Ubuntu, however, this won’t work. As a user with sudo permissions (the user created on install has these) enter the following instead:  
sudo su
  Enter your account password and voila, you are logged in as root. You can tell when you are logged in as root as your prompt will look like:  
[email protected]:/home/#
  rather than:  
[email protected]:/home$  
  Note the # rather than the $? This indicates that you’re performing actions as the root user. This can be dangerous as you will be able to do things which can wreck your system irreparably, so be careful! To go back to working as your usual user, type:  
exit
  or hit CTRL+D.

Ubuntu Server Benchmarks: Geekbench

  This is one of our favourite benchmarks for Ubuntu Server – it’s cross-platform, meaning that it can be ran on Windows, Mac OS X, Ubuntu Desktop, Ubuntu Server and more. You can get the download link from the following site:  
http://www.primatelabs.com/geekbench/download/linux/
  Currently this works:  
wget http://d34wv75roto0rl.cloudfront.net/Geekbench-2.4.2-Linux.tar.gz
  Unzip:  
gunzip Geekbench-2.4.2-Linux.tar.gz
  Untar:  
tar -xvf Geekbench-2.4.2-Linux.tar.gz
  Change directory to the new files:  
cd dist/Geekbench-2.4.2-Linux
  If you have a license key, enter it like so:  
./geekbench_x86_64 -r [youremail] [license]
  Then run the 64-bit:  
./geekbench_x86_64
  If you don’t, use the 32-bit version:  
./geekbench_x86_32
  Note! If you haven’t installed the ia32-libs package the 32-bit Geekbench will not work on a 64-bit system! Running the benchmarks will give you output similar to the following – a brief rundown of the system setup followed by the benchmark results as they happen:  
System Information Operating System      Ubuntu 12.04.2 LTS 3.2.0-38-generic x86_64 Model                 VMware, Inc. VMware Virtual Platform Motherboard           Intel Corporation 440BX Desktop Reference Platform Processor             Intel Xeon E5-2630 @ 2.30 GHz 2 Processors, 6 Cores, 6 Threads Processor ID          GenuineIntel Family 6 Model 45 Stepping 7 L1 Instruction Cache  32.0 KB L1 Data Cache         32.0 KB L2 Cache              256 KB L3 Cache              15.0 MB Memory                19.6 GB BIOS                  Phoenix Technologies LTD 6.00 Integer Blowfish single-threaded scalar   1647 |||||| multi-threaded scalar   10574 |||||||||||||||||||||||||||||||||||||||| Text Compress single-threaded scalar   2485 ||||||||| multi-threaded scalar   14490 |||||||||||||||||||||||||||||||||||||||| Text Decompress single-threaded scalar   2980 ||||||||||| multi-threaded scalar   18177 |||||||||||||||||||||||||||||||||||||||| Image Compress single-threaded scalar   2208 |||||||| multi-threaded scalar   12950 |||||||||||||||||||||||||||||||||||||||| Image Decompress single-threaded scalar   2733 |||||||||| multi-threaded scalar   16503 |||||||||||||||||||||||||||||||||||||||| Lua single-threaded scalar   4460 ||||||||||||||||| multi-threaded scalar   26572 |||||||||||||||||||||||||||||||||||||||| Floating Point Mandelbrot single-threaded scalar   2194 |||||||| multi-threaded scalar   13365 |||||||||||||||||||||||||||||||||||||||| Dot Product single-threaded scalar   3558 |||||||||||||| multi-threaded scalar   22600 |||||||||||||||||||||||||||||||||||||||| single-threaded vector   4130 |||||||||||||||| multi-threaded vector   29112 |||||||||||||||||||||||||||||||||||||||| LU Decomposition single-threaded scalar   2791 ||||||||||| multi-threaded scalar   16599 |||||||||||||||||||||||||||||||||||||||| Primality Test single-threaded scalar   6190 |||||||||||||||||||||||| multi-threaded scalar   29957 |||||||||||||||||||||||||||||||||||||||| Sharpen Image single-threaded scalar   5657 |||||||||||||||||||||| multi-threaded scalar   34118 |||||||||||||||||||||||||||||||||||||||| Blur Image single-threaded scalar   2287 ||||||||| multi-threaded scalar   13782 |||||||||||||||||||||||||||||||||||||||| Memory Read Sequential single-threaded scalar   4657 |||||||||||||||||| Write Sequential single-threaded scalar   6769 ||||||||||||||||||||||||||| Stdlib Allocate single-threaded scalar   4084 |||||||||||||||| Stdlib Write single-threaded scalar   1872 ||||||| Stdlib Copy single-threaded scalar   3674 |||||||||||||| Stream Stream Copy single-threaded scalar   5435 ||||||||||||||||||||| single-threaded vector   7031 |||||||||||||||||||||||||||| Stream Scale single-threaded scalar   5668 |||||||||||||||||||||| single-threaded vector   6441 ||||||||||||||||||||||||| Stream Add single-threaded scalar   5311 ||||||||||||||||||||| single-threaded vector   7203 |||||||||||||||||||||||||||| Stream Triad single-threaded scalar   5556 |||||||||||||||||||||| single-threaded vector   5082 |||||||||||||||||||| Benchmark Summary Integer Score              9648 |||||||||||||||||||||||||||||||||||||| Floating Point Score      13310 |||||||||||||||||||||||||||||||||||||||| Memory Score               4211 |||||||||||||||| Stream Score               5965 ||||||||||||||||||||||| Geekbench Score            9474 ||||||||||||||||||||||||||||||||||||| Upload results to the Geekbench Browser? [Y/n]    
If you upload the results, you can add them to a Geekbench account by accessing a web link – such as:  
Upload results to the Geekbench Browser? [Y/n]y Uploading results to the Geekbench Browser. This could take a minute or two depending on the speed of your internet connection. Upload succeeded. Visit the following link and view your results online: http://browser.primatelabs.com/geekbench2/18911 Visit the following link and add this result to your profile: http://browser.primatelabs.com/geekbench2/claim/18911?key=572432 [email protected]:/home/tma1/geekbench/dist/Geekbench-2.4.2-Linux#  
Put the address it gives you into a browser and you will be able to gather results over time to compare systems/virtual machines! Geekbench is one of the best Ubuntu Server benchmarks that we have come across – it provides you with a range of tests which are easy to compare, as well as giving you an overall score figure to give you an idea of how the system performs overall vs. other setups. The fact that it is cross-platform is a great bonus, too, as it means you can test the efficiency and performance of a variety of operating systems on the same hardware/virtual hardware setups – and the results can be very interesting. Highly recommended!

Ubuntu Server Benchmarks: Hardinfo

  Hardinfo is one of the command-line benchmarks available for Ubuntu Server – it does have graphical features so it will also be useful for Ubuntu Desktop users, but for the purpose of this piece we will assume you’re at a terminal. It not only runs benchmarks like Blowfish but also shows you a great deal of information about the system itself, like ARP tables, sensors, CPU/RAM details and more.   To install, run the following:  
sudo apt-get install hardinfo
  You can run it without using less to view the results, but you’ll probably want to pipe the results to less to make it a bit easier to navigate the pages of text. Run it with the following:  
hardinfo | less
  This pipes the output to the “less” command – once the command completes you will be able to navigate the results with the up/down and pageup/pagedown keys. To quit less press “q”. At the bottom of the results are the benchmarks; they will look something akin to this:   ubuntuBenchmark-hardinfo   The benchmark in this case was run on an ESXi VM with two 2.3GHz CPUs. It’s not the prettiest output but it provides quite a bit of potentially useful information. The output from hardinfo is a whole lot prettier when you have a GUI!

Monitoring network usage on Ubuntu

  If you want to see how much traffic is passing through your network port there’s a handy tool called vnstat which will tally the amount of data passing through. You can install it with:  
sudo apt-get install vnstat
  It will usually add the databases and network ports automatically like so:   vnstat-0   If it doesn’t and gives you an error you can create the database(s) with:  
sudo vnstat -u -i eth0
  If you have multiple network cards/ports you can add those in, too:  
vnstat -u -i eth1 vnstat -u -i eth2 …etc  
If it couldn’t create the databases you can start it with:  
sudo /etc/init.d/vnstat start  
If you need to change the maximum bandwidth from 100Mb you can edit the file:  
/etc/vnstat.conf
  Scroll down until you see the following:  
# maximum bandwidth (Mbit) for all interfaces, 0 = disable feature # (unless interface specific limit is given) MaxBandwidth 100
  and make MaxBandwidth the figure you require (e.g. 1000). If you make a change restart vnstat with:  
/etc/init.d/vnstat restart
  You can now see how much traffic has come through the NIC since vnstat started recording – at first it probably won’t be much (if any), but as it adds up you can check it with:  
vnstat
  The output should look like:   vnstat-01   You can watch how much traffic is flowing through in real-time by running:  
vnstat -i eth0 -l
  This will give you a screen showing you the current traffic:   vnstat-02   You can end this with CTRL+C, which shows you a summary screen:   vnstat-03   You can get an hourly summary with:  
vnstat -i eth0 -h
  vnstat-04 vnstat-05   Daily summary with:  
vnstat -i eth0 -d
  vnstat-04 Monthly summary with:  
vnstat -i eth0 -m
  vnstat-06   This is a really handy way of keeping track of your network traffic – whether it’s out of curiosity, wanting to know how much stress your network is under or looking for a bottleneck this can be quite a valuable tool.

How to restart NFS server on Ubuntu

  Once you set up your NFS exports by adding lines to /etc/exports you need to restart your NFS server; do this with the following:  
sudo /etc/init.d/nfs-kernel-server restart
  You should see output along the lines of:
 * Stopping NFS kernel daemon                 [ OK ] * Unexporting directories for NFS kernel daemon…           [ OK ] * Exporting directories for NFS kernel daemon… exportfs: /etc/exports [1]: Neither ‘subtree_check’ or ‘no_subtree_check’ specified for export “10.1.1.87/24:/nfs/sharedDir”. Assuming default behaviour (‘no_subtree_check’). NOTE: this default has changed since nfs-utils version 1.0.x
  Assuming no error messages pop up here you should now try to connect to your NFS share.

ESXi: Accessing datastores via web browser

  This is one that a lot of people don’t seem to be aware of – did you know you could access your ESXi server’s datastores via a browser? It’s a convenient way of grabbing copies of ISOs or patches stored on your server for burning or use elsewhere. It’s set up automatically with ESXi – simply enter in the IP address of your local ESXi server and you should see a page akin to the following:  

Click on the link on the right-hand side to view the datastores and you will be prompted for a login:   Enter your login – usually the root login you created when you installed ESXi. From there you should be taken to a page where you can see a listing of all of your available datastores:   From there you can browse the contents of the datastores and download files as you please! It can also be handy as a quick way of viewing log files.