create usb install for esx / esxi

First format your usb / flash drive with FAT. Then copy all the contents of the installer .iso onto the drive.

Next delete isolinux.bin and rename isolinux.cfg to syslinux.cfg

Edit syslinux.cfg and append “usb” to the line starting with “append” … i.e. similar to this

append vmkboot.gz — vmkernel.gz — sys.vgz — cim.vgz — ienviron.tgz — image.tgz — install.tgz usb

Next grab the latest syslinux.exe (zip for windows) from here and run syslinux -s –ma <driveletter>:


boot esx from usb drive

Its quite easy to boot esx from a usb device or flash card..

First download the .iso, then browse with winrar or similar. See if you can find the “big”.dd file this is the file we need.

i.e. the ESXi 4 file is called VMware-VMvisor-big-208167-x86_64.dd

Next grab WinImage and “restore image to physical harddrive” choose the .dd file the select your usb / flash drive.


Linux – crontab

Time to schedule some tasks!

First you need to make sure your in the /etc/cron.d/cron.allow file. If you are not SU to root and add yourself into it.

Now to create your new crontab file;

crontab -e

You are in vi in your newly created crontab file (note if you do not have access to do this it will say so)

Now, i’m no expert at using vi, but if you press i you will go into insert mode. Do this, then type the cron job details. A typical cron job will look like this

0 4 * * * /export/home/user/

so there are five slots before the command you want to run. They are: min, hour, day, month, day-week. So my example above will run at 4am every day. See below for more detail.

once you have entered the line press ESC then type :wq to save and quit.

To confirm the job has been saved successfully in cron type this command;

crontab -l  this will show you your current scheduled tasks, it should output the above job.

In OpenSolaris the crontab files are located at /var/spool/cron/crontabs/ they are named after the specific user. Sometimes its easier to go there than to use vi, but make sure your permissions are all set correctly before editing any system files.

In some distros there are folders like /etc/cron.daily/ which run any scripts inside them on a schedule matching the folder name.

This is a bit more on the format of the 5 timings within the crontab file;

*     *   *   *    *  command to be executed

|     |     |     |     |
|     |     |     |     +—– day of week (0 – 6) (Sunday=0)
|     |     |     +——- month (1 – 12)
|     |     +——— day of month (1 – 31)
|     +———– hour (0 – 23)
+————- min (0 – 59)


@reboot is also another very handy cron modifier. I use the following quite a lot…
@reboot /bin/sleep 600 ; /path/to/your/your_program@reboot /bin/sleep 600 ; /path/to/your/your_program