Hardware Reference
In-Depth Information
Now check to see you have
relatime
enabled by using this command:
# mount
This will display all mounted filesystems and their mount options. In Figure
2-15
you can see that the
relatime
option has been added to the filesystem mount options.
Figure 2-15.
Filesystems mounted with relatime
Thinking About Swapping
Given that the Raspberry Pi has limited amounts of system memory you would assume a swap device or swap file
would help out.
WhY YOU DON't NeeD tO Care aBOUt SWap
In the Linux and Unix world, machines are configured to have a swap space on disk. A swap space acts like
additional system memory; it's just a lot slower. If your machine were to run low on system memory it may
choose to swap a process running in memory to disk.
With a normal hard disk you would be correct on this assumption. Once again it comes back to the flash cell
cycles. A swap would consume a large amount of cycles on the SD card, which in turn would dramatically reduce the
life of your SD card. This is yet another reason why it's important to have your Raspberry Pi set up to best utilize the
resources at hand. It's all about understanding the hardware and its limitations.
Optimizing CPU Cycles
Because CPU cycles are precious, a static IP address will be better suited for headless operation. Therefore, I will show
you how to first set up the machine to boot with a static IP address. By having a static IP address you won't need to run
a DHCP client agent, thus saving a small amount of CPU cycles. This is an optional step, but I feel it's wise to give a
headless device a static IP address. The reason behind this is that if your machine is headless you won't be able to see
the IP address that the DHCP server has given out to your Raspberry Pi. A static IP solves this issue. If you wish to leave
your machine on DHCP you don't need to do anything because the Fedora image is configured to use DHCP by default.
