"In Btrfs there the solid-state drive mode can be
enabled by using the -o ssd mount option or adding ssd to the
/etc/fstab. Enabling this option will tune the Btrfs allocator for
SSD usage, which is then designed to improve performance with this
file-system still undergoing development. However, unless disabling
the write cache for the drive, the SSD mode does not necessarily
mean better performance. In fact, as our results are about to show,
the quantitative disk performance can drop greatly in the SSD mode
when the write cache remains enabled. However, not all write caches
can be easily disabled right now under Linux. With the OCZ Vertex
SATA 2.0 SSD, which we used for this testing today, had its write
caching always enabled. When attempting to disable the write cache
through hdparm it would remain enabled regardless and when using
sdparm it would report change_mode_page: failed setting page:
Caching (SBC).
"The test system for this article included an Intel Core 2 Duo
E8400 clocked at 4.00GHz, an ASUS P5E64 WS Professional
motherboard, 2GB of OCZ DDR3-1333MHz system memory, an OCZ 64GB
Vertex (v1.10 firmware) Serial ATA 2.0 SSD, and a NVIDIA GeForce
9500GT graphics card. On the software side was Fedora 11 with all
Rawhide updates as of the 28th of May, 2009. The kernel was Linux
2.6.29.4, GNOME 2.26.1 was the desktop, the X Server was 1.6.2 RC1,
xf86-video-nouveau display driver, GCC 4.4.0, and at installation
time through Anaconda we setup the drive to using Btrfs."