If this isn't an option, you can make other changes to reduce the frequency of writes to these directories. For instance, you can increase the severity of log messages which will be recorded by editing the /etc/rsyslog.conf file (see man rsyslog. conf for details), or you can decrease your system's 'swappiness', which encourages it to use swap space less frequently. You can do this by executing:
echo 1 > /proc/sys/vm/ swappiness
Our test drives
The underlying storage technology in most SSDs varies little. What makes the biggest difference to their performance is the controller and firmware - the hardware that decides how and where to write your data on the drive.
A bad controller can slow your drive down, particularly as it ages, and can lead to varying performance across different-sized writes (eg, 4k vs 9k).
The two test drives that we have represent two competing controller solutions. The Crucial M4 uses a Marvell controller, while our Intel 330 uses a Sandforce one. These same controllers are used on many different drives, so our results will be able to inform your buying decisions, even if you don't choose either of the specific drives we have on test.
We tested the drives using the Postmark, Compile Bench and Kernel Unpacking tests in the Phoronix Test Suite, with a view to seeing how the drives performed in real situations. All of the tests were carried out on an Ubuntu 12.04 system, with ext4 and the discard option set in /etc/fstab.
The Compile Bench test is perhaps the most interesting, as it's operations attempt to simulate operations that age a file-system - the most likely scenario to tax the controller. On these tests, the Intel drive, with a Sandforce controller, performed much better.
That said, the Crucial drive was much quicker when it came to dealing with many small files in the PostMark test, and marginally better when unpacking the kernel.
Both drives are in the same price bracket, being available online anywhere from £84 and upwards.
