SSD caching for RAID arrays?

[Quiver]

I have a mass storage RAID 5 array that uses 3 WD green 2TB drives (the 5400rpm ones). I would love to be able to use caching and retain redundancy. I am wondering if its possible to use some of these new (yea I know its just software gimickry, thats why I have hope) drives in a RAID 1 configuration as a cache drive for my mass storage array. Writes (my biggest problem) would speed up a ton. Not to concerned with read speed, I just need to be able to get data to the array faster than it can currently handle in bursts.

Anyone know of a way to do this? I was thinking to just make a hardware raid 1 array with a couple SSDs and find software somewhere to do it with. What software do you guys know of that would support this? Thanks in advance guys!

 

[farrengottu]

im pretty sure there is nothing that will do this.

ssd cacheing is meant to speed up read speed. it does this by copying commonly used files from the HDD to the SSD. so that when you need a common file its can be accessed quickly.

in a writeing scenario it would just write to the SSD then once the SSD is full it would have to wait until the HDD could catch up. so for small burst speeds it would be kinda usefull but for anything larger than the available space on the ssd it would be a short lived boost. but based on this alone its not a terrible idea. with a very large SSD you would likely never see the slowdown.

what makes this a bad idea is that SSDs are overall bad for writing. they can only be written to so many times before parts of the drive become unusable. normally this will take a decade to really effect the drive but in the setup you suggest i bet it could be a big problem in less than a year.

most importantly is that SSD caching is a type of raid. and so far there isnt any types of raid that merge SSD caching with traditional raid types. i suspect they will be around soon but not to accomodate writing. it will likely just be for reading as SSD caching is.


i could be wrong about a few points here but thats the info ive come across.
feel free to research away.