Craig Mayhew’s Blog

By Default Ubuntu will move data in RAM onto the swap file/partition on the hard disk long before it runs out of memory. It will pick data that isn’t accessed often but this can still be an annoying slow down on the system. To prevent the over use of SWAP space and speed things up all we need to do is change one setting… swappiness.

Swappiness can be set from 0 to 100. The default is 60 and the lower it is the more the computer will try to keep everything in RAM.

If you want to temporarily change the swappiness then run this command with desired swappiness level:

sudo sysctl vm.swappiness=10

Alternatively if you want the change to be permanent then edit this file:

sudo gedit /etc/sysctl.conf

Set swappiness to the desired level (in this case 1) by either modifying this line in the file “/etc/sysctl.conf” or if it doesn’t exist, add it at the end.

vm.swappiness=1

Reboot the computer for the change to take effect.

I found the ntfs-3g process was using 100% cpu. Apparently VMWARE can thrash the hard drive so the workaround is to set “mainMem.useNamedFile=FALSE” in the virtual machines .vmx file and VMware will perform faster.

E text editor recently started instantly crashing no matter how I opened it. The fix was to delete or rename the “config.db” and “e.db” files in the following directory (be sure to replace %username% with your actual windows username):

C:\Users\%username%\AppData\Roaming\e

If you’ve got GooSync on your mobile phone and it suddenly refuses to sync spouting a “511″ error code then simply log into your GooSync account (via a web browser) and reselect your mobile device (click the picture of your device). This worked for me and had been a problem for the last few days.

I imagine they have a database error where they no longer know what device you are using…

Ubuntu has started being a little slow to boot, as it turns out one of the drives was the cause of this. During the boot up processes ubuntu would hang for a while and then spit out the following: “ata8: SRST failed (error:-16)”. It seems one of my drives wasn’t responding properly during boot up.

To fix this I tried:

- Disabling floppy drive in bios (This didn’t help, but I’m sure it will speed things up slightly as I don’t have a floppy drive)
- Set the “IDE detect time out (sec)” to 0. It was originally 35. (This didn’t help. Be careful when changing this option if you are using IDE drives)
- Unplugged the SATA cable from my DVD drive and plugged it back in again. (PROBLEM SOLVED!)

I imagine either my sata cable is slightly loose or dodgy and reseating it has sorted the problem. If the problem occurs again then I will replace the cable.

After logging into my Ubuntu 9.04 machine I’m greeted with the following message “Cannot find or run the base session script. Running Gnome in failsafe session instead”. The reason for this was I had messed up my permissions and the following fixed it:

After logging in and recieving the errors message press Ctrl-Alt-F1 to drop back into command line. Then run the following:

Sudo chmod 755 /etc/gdm/Xsession

If for whatever reason you change the permissions on your sudoers file you will get a similar error to “sudo: /etc/sudoers is mode 0640, should be 0440″ whenever you try to run the sudo command. The problem is that because the permissions are wrong on the sudoers file, linux won’t let you run the sudo command!

To get around this press “Esc” at the grub loader screen when linux is booting and enter into the latest recovery mode. Then select the option that allows you to drop into a command line as root and type

chmod 0440 /etc/sudoers

Then reboot and your troubles should be solved!

A Friend of mine called Szymon pointed me in the direction of this very neat little app called PIM Backup. It’s currently on version 2.8 and available for free from here: www.dotfred.net.

Instead of being frustrated with the bloated active sync software that Microsoft provides simply copy the PIM backup application onto your device. Then run the application via the phone’s file explorer. Select your options and it will then backup your data into a compressed file called a “.pib” file. Copy a backup of the app and the .pib file onto CD/DVD and there you go, one very quick backup!

From this day forth I see the Drobo as useful as volatile storage when it comes to long term storage of my data.

How it happened:
I unplugged the Drobo from an old computer using the now ancient USB 1.1 and plugged it into my Ubuntu computer. The Ubuntu computer gave a message saying it couldn’t mount the volume. So I plugged it into my laptop to see what Vista had to say, but unfortunately Vista refused to mount the drive as well. After checking the drive in Vista’s disk manager I came to conclusion that Vista saw it as a RAW partition! It had completely forgotten that it was an NTFS partition so Vista didn’t know what to do with it.

My immediate thought was the Drobo is going to start freeing up space and wiping the drives sector by sector. Fortunately I couldn’t hear any disk activity so I thought to myself that I may be able to recover the data. I used a copy of EASUES Data Recovery to do a scan of the hard disk to find lost partitions. It took 48 hours to do the scan, which is ridiculous when you consider I only had 300GB of data on the Drobo and the Drobo’s entire capacity was only 500GB, 48 hours is fairly ridiculous at 1.7Mb/s.

At this point my laptop where I was recovering the data to, crashed. Not a problem as I had my initial scan saved so I could continue where I left off. I wandered off for 2 minutes to come back and find my computer had started a file system scan of the Drobo and it had attempted to repair damaged sectors!! This could be really good or really bad. After windows booted and I franticly continued the scan I ran into another problem! The scan had not remembered where it had stopped so I had to leave it running for a further 48 hours! This time around however I had the mortifying experience of watching the little blue lights go out one at a time on the Drobo’s front panel. It appears that the file system “fix” that vista had run had in fact instructed the Drobo to truncate the “problem” parts of the disk. This consequently meant that I was running the scan for the second time and that this time the Drobo was probably slowly destroying my data. As it turned out the file system scan had destroyed a lot of data but in the end I managed to get a portion of my data back.

Important lessons:

• If you delete something from a drobo, your data is gone… forever.
• If you Drobo file system gets damaged, do not let windows or any other operating system repair it or you will lose some or all of your data.
• The drobo is slow, you can’t recover data in a timely manner (if you can recover it at all).
• Don’t trust the Drobo, as it is only a single device it cannot provide an ultimate solution (or even a reliable one). I will be moving to some kind of distributed private cloud storage setup and will blog about that when I’ve got one going.
• During the time that I have owned the Drobo, it has failed twice. No other disks, flash drives or dvds have died in my house since I bought the drobo. So the Drobo fails more often than any of my other storage devices.

Download VMWare Server from http://www.vmware.com/products/server/

Extract the tar file to somewhere convenient, in this case I’m going to extract it to the desktop.

Execute vmware-install.pl which is in the vmware-server-distrib folder that you just extracted. You will be prompted by questions about install directories. I managed to get away with pushing enter for the default value on all of these questions. It may need to recompile some files if it isn’t familiar with your kernel version. This isn’t normally a problem if you have a c/c++ compiler.

If you don’t have a c++ compile (here’s how to check and install one) then get one from synaptic packaged manager.

When asked, make sure you respond “yes” and give your ubuntu username when prompted to change the username (if this bit goes wrong then once VMWare Server is installed you will need to uninstall it and start over). After answering more prompts the installer will ask for your serial number. This can be obtained from the VMWare website for free.

Caveats:

1) If you accidentaly left the username blank then you will need to run the following command to uninstall the vmware server. You will then need to start the install again.

sudo /usr/bin/vmware-uninstall.pl

2) To access the server admin you need to visit either https://127.0.0.1:8333/ui/ or http://127.0.0.1:8222/ui/ in a browser. You can then login with your ubuntu account username and password.