Mostly Harmless

Mostly about my amusement

Tag: Linux (page 1 of 3)

February 5, 2011

Opensource is still the best

As part of my ongoing home IT challenges I have set up a basement server running Ubuntu 10.04 LTS. My normal method of managing my servers is to do everything by ssh.

That’s geeky, but not much fun. So I looked for a free X server and came across Xming. It’s a not GPL’ed but is it freely available and the license is not burdensome.

Using XLaunch, I setup the parameters I want and saved that to a file. That .xlaunch file extension is registered to Xming so I just need to double-click the icon and it starts my desktop remotely using X windows.I’ve got the desktop in a neat 1280×1024 window using “-screen 0 1280 1024” as an Xming command line argument.

The only problem I am having is that I am launching gnome-session and it’s not exiting cleanly at then of my session. Most likely that’s not quiet the right program to initiate an X session but for now it’s acceptable.

July 23, 2009

Ubuntu UNR 9.04 performance boost

My Acer Aspire One netbook is good but the 8GB SSD drive that it shipped with is still the biggest drawback.  When I want to view HQ or regular YouTube clip (forget about HD), the SSD gets accessed and performance takes a dive. Videos stutter and playback is horrible.

After looking at the ApireOne community documentation page again I came across two tweaks that really helps a lot.  These are covered here at the Geek Sheet.

The first tweak is to mount the SSD switching the option from “relatime to “noatime”.

From the article:

Tweak #3: Change the file system mount options on SSDs to “noatime”. On certain Linux distributions, such as Ubuntu, the default is “relatime”. This tells the kernel to write the Last Accessed Time attribute on files. Conversely, “noatime” tells the kernel not to write them, which considerably improves performance. Linus himself suggests using it in circumstances such as this, so therefore, I consider it to be gospel.

The second tweek is on the kernel line in /boot/grub/menu.lst, right after splash, insert the option “elevator=noop”.  This will let you use the “noop” I/O scheduler.  The SSD is not a hard disk and there is no platter to optimize.

These combined reduces the amount of writes to the SSD and I am now able to view this whole episode of Gundam 00 in HQ. Before these changes I could not have done this.

Considering that my main desktop PC is dying and needs to be replaced, having an optimized netbook is not a bad thing at all.

May 17, 2009

Acer Aspire One UNR 9.04 settings

Sometimes I post things to be able to recall 6 months later what I did. This is one of those “I’d better write this down” articles.

After a couple of iterations, my Acer Aspire One Netbook runs well on Ubuntu Netbook Remix 9.04. Here’s what I did.

I created one root 8 GB filesystem formatted in ext2 with no swap space. I don’t know why but using ext3 (a journaling filesystem) and/or swap meant poor performance. It’s probably due to the SSD not handling the read/writes well.

Following the advice from the Ubuntu AspireOne documentation page, I installed linux-backports-jaunty-modules and ran all the updates.  Among other things this gets the wireless LED working. UNR 9.04 is still young yet so it’s not a lot of updates.

In my /boot/grub/menu.lst file I added “enable_mtrr_cleanup pciehp.pciehp_force=1” to my defoption line and kernel line. The mtrr_cleanup is to allow the X server to take advantage of a performance boost and with the pciehp I can use both SD card readers without any problem.

After using lspci to get the correct values, I added this line to my /etc/rc.local

echo "base=0x40000000 size=0x10000000 type=write-combining" > /proc/mtrr

The mtrr part is for improving video performance, the pciehp portion is to get both SD card readers working.

With these settings, the netbook is working well with only a few caveats.  Youtube is still jumpy and slow. But I got this netbook to play with Ubuntu, ssh to my servers, and view web pages so I’m satisfied.

April 23, 2009

Ubuntu Netbook Remix 9.04

The nice thing about my netbook is that I have no hesitation to wipe it clean and install a new OS on it. Which is what I did today after I downloaded Ubuntu Netbook Remix 9.04.

904-netbook-remix

It was released today and the instructions for installing off of a USB stick were very clear. It’s a very slick package and for what I am doing with Firefox and Gnome Terminal it’s more than enough. The menu system is replaced with a compatible front end that lets you create a favorites page and launch apps from there. And unlike the recently talked about”floats like a lead baloon” Windows 7 Starter, I can easily run more than three apps at a time.

I’m writing this on my netbook and I still need to optimize the environment for speed. But so far so good.

April 22, 2009

Aspire One Netbook

After I returned my defective Dell MINI 9, I shopped around for a replacement. I found a better deal with the Acer Aspire One AOA110-1588 from J&R Music. It was on sale for $229.99 and had free shipping.

From the product web page

  • Intel Atom N270 1.6 GHz Processor
  • 512 KB L2 Cache, 533 MHz Front Bus speed
  • 1024 MB DDR2 (PC2-4200) RAM
  • 16GB total Memory (8GB Solid state Drive & 8GB external SD card)
  • 8.9″ diagonal WSVGA (1024 x 600) Acer CrystalBrite Display
  • Integrated Acer Crystal Eye Webcam with Microphone
  • Intel Graphics Media Accelerator 950
  • Built-in Stereo Speakers
  • Acer InviLink 802.11b/g Wireless
  • 10/100 Ethernet LAN
  • Multi-in-1 Card Reader SD, MMC, RS-MMC, MS, MS Pro, xD
  • 3 x USB 2.0, Headphone/Speaker/Line-Out, Microphone-in, VGA, RJ-45 (LAN)
  • Approximate Unit Dimensions: 9.8″ (W) x 6.7″ (D) x 1.14″ (H)
  • Approximate Unit Weight: 2.5 Pounds

It’s tiny. It rained yesterday and I fit the netbook into a zip lock bag to keep it dry.

Once I unpacked it, I downloaded all of the required XP updates. That took over 2 hours. Getting the McAfee 60 day trial updated and registered took another 30 minutes.

No matter how I kicked it around and configured it, I could not get it to work quickly. Applications ran but the netbook would pause for seconds at a time. Something in Windows XP was causing it to stutter. I removed McAfee and installed Norton 360 (it comes with 3 PC licenses and I have a spare) and that seemed to made the netbook more responsive but the stutter would come back whenever XP accessed the 8GB SSD drive.

So I fixed it by installing Ubuntu 8.10 via a USB stick.

I wiped out the whole XP install, hooked up the ethernet to my LAN and ran the install and then the update. The update refreshed 291 packages. The whole process is documented at https://help.ubuntu.com/community/AspireOne110L and is very straight forward. Once the updates were applied, I was able to get the ath5k wireless driver working in no time.

Now I have a Linux netbook just like I wanted and no stutter.

The 1024×600 is a little constrained but viewing web pages and hitting the F11 key makes it all better.  The keyboard took some adjustments on my part but it’s all good. I did hook up a wireless mouse to it but on the couch or in bed the touch pad is very usable. Overall I am very satisfied with how it performs.

November 30, 2008

Dead Xbox 360 MTU issue

For months my Xbox 360 has been complaining about the MTU being too small on my Internet gateway. This meant no updates and Xbox Live stopped working. I’ve been busy so I did not give it much thought.

My brother Alek bought a new one  for his apartment and hooked it up at my house.  I figured that the MTU problem was an issue with my old Xbox 360. Naturally it wasn’t.  His had the same problem so I looked at my Linux gateway.  Running ifconfig on my server showed me that the MTU on the external interface was set to 576.

How did that happen? I thought it defaulted to 1500. I ran the command “ifconfig eth1 mtu 1500” and that fixed the problem right away.  On my openSUSE server I edited the file /etc/sysconfig/network/ifcfg-eth1 and made the MTU line read MTU=’1500′. This way when my box reboots the MTU setting should go to 1500.

After that was done, Alek was able to download the “new Xbox Experience”.  The irony is that Friday night my Xbox 360 finally gave up the ghost and died.  It’s out of warranty so I’ll be heading to Best Buy to get the holiday bundle.

September 21, 2008

Upgrade of VPS from Ubuntu 6.06 LTS to 8.04 LTS

My upgrade from Ubuntu 6.06 LTS = FAIL.

Last week I created a VPS on Slicehost.  I’ve been using Tektonic for a while now and have no complaints.  The support is very good and I can backup my VPS for when I need to.

I’m using Slicehost because I don’t want both of my domain DNS servers on the same provider. They offer Ubuntu 8.04 LTS, runs on top of Xen, and provide console access via an Ajax web front end.  You need to pay extra for a backup option. Aside from that one little point, using Slicehost is ridiculously easy and very manageable. They eat their own dog food and it shows.

On my Tektonic VPS it’s running on top of Virtuozzo.  No console just ssh but I do get to make a backup of my VPS and re-installing is a breeze. My only complaint is that it’s running Ubuntu 6.06 LTS which is a little dated.  For example the subversion client is 1.3.2 and I’d like to see more current versions such as 1.5.x.  On Ubuntu 8.04 LTS I just added the backports repository and I get current versions of packages.

Switching to Ubuntu 8.04 LTS should be simple. As root I ran these commands:

apt-get update
apt-get upgrade
apt-get install update-manager-core
do-release-upgrade

This is a seamless process and aside from asking me some questions, I had no issues.  The only issue I had is when I rebooted my VPS, it left the VPS un-bootable.  The support tech that I chatted with had not seen that before.  My VPS would not even start and I had to re-install it.

I’m now restoring the VPS to the backup I made yesterday, so it’s not all a total wash.  Most likely I’ll work with Tektonic to get 8.04 LTS on that slice provided they offer it.  Ubuntu 6.06 LTS is still supported so aside from consistency across servers, this is not a big deal for me.

June 16, 2008

WordPress file monitoring

Over a week ago I complained about WordPress users crying security wolf and not being able to recover their blog when the “Bad Thing(tm)” happens.

Since then a real brawl developed on the support forum that could be summed up like so:

  1. One or more users is insisting that there is an XMLRPC exploit in 2.5.1.
  2. The same one or more users refuses to back this claim up with data, or apparently send the WordPress security e-mail alias any info (maybe, how would other people know what was sent via e-mail?)
  3. Many people tried to reasonably explain that such an exploit may exist but without data there is nothing to solve.

This discussion was just plain nuts and went around in circles.  Complaining about a problem without providing any proof and then getting all pissy about it is totally useless.  It is entirely possible that such an exploit exists and many people replied so.  But without any providing data other than saying “I can assure you that the hack occurs via XMLRPC”, then everyone’s time gets wasted.

Fortunately, Donncha provided a page that covers the issue succinctly and today he added another post on setting up aide.  His two posts are good and anyone considering monitoring their WordPress files for modification should give this a try.

Aide will let you see if your installation files and directories have been tampered with.  It won’t protect you against HTTP POSTS or database attacks but it’s very good if someone succeeds in modifying your files.

There are ways to log what’s being sent via an HTTP POST and examine that information; if (or even when) I get hacked, I’ll try to start looking at that data.  MYSQL database monitoring, that could be interesting but for now I’m not aware of a good tool to do that.

On my OpenSuSE installation, installing aide is simple.  As root run

zypper install aide
aide --init
mv /var/lib/aide/aide.db.new /var/lib/aide/aide.db
aide --check
cp /usr/share/doc/packages/aide/examples/etc/cron.daily/aide.sh /etc/cron.daily/

All of which I just did.  I ran the check option to make sure I did not create any issues with the aide.conf file.  I’ll play with the aide.conf file and see what kind of output I get when the daily cron job gets run.  If I add and modify files and I set it up correctly then I should see that in daily cron job’s output.

Update: this worked but in /etc/aide.conf change the line verbose=1 to verbose=5.  That will get you a useful output of which files and directories changed.

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Jan Dembowski

Jan Dembowski

I am a software enthusiast who is easily amused and definitely mostly harmless.

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