If you are wondering what a ramdisk is, it is simply using your physical RAM memory as a temporary storage drive. Instead of writing to disk, you are writing files to memory.
And the results of my testing?
Well, I'll let these pictures speak for themselves:
1st. Ramdisk. Average read 1.2Gb/s. As in Gigabytes per second. An entire full DVD movie worth of data would take less than 5 seconds to copy.
2nd,Corsair F120 Sandforce based SSD. Read speed bench at 234 Mb/s which is no slouch and faster than any platter drive. The same DVD would take roughly 22 seconds.
Compared to a standard platter HDD drive, a DVD would take 81 seconds at 60Mb/sec. A 10Mb/sec USB stick would take 486 seconds or 8 minutes to copy.
I tried a Virtual Box VDI image in ramdisk and an ubuntu 10.10 image loaded in less than 6 seconds.
Here is how you make a ramdisk:
mkdir -p /tmp/ramdisk sudo mount -t tmpfs -o
size=1024M tmpfs /tmp/ramdisk
Or, you can simply copy files to /dev/shm/ but you risk saturating all your available ram. By using tmpfs, you can set a limit. In my example, my ramdisk is 1GB.
It should be noted that ramdisks are not persistent. They will need to be recreated upon reboot. You lose the data in ramdisk when your power down.
I am currently exploring options for a real-time ffmpeg transcoding system that will write and read quite a bit to disk. I also have another use case scenario with imagemagick/ghostscript writing large temp files of PDFs. A ramdisk may be the way to go.
There is another interesting use of ramdisk. To run a completely private and secure micro servers like tor-ramdisk to evade police authority. Data would simply disappear upon a power down. If the authority seized your equipment, all the data would simply vanish and make it harder for forensic analysis.
Now, I just need a laptop with 32GB of RAM.