On 01/27/2015 11:20 AM, Yasha Karant wrote:
> There are hybrid disk drives that have a "small" SSD flash memory along
> with the regular spinning media, typically to serve as a cache for lower
> latency.  Does anyone have long term experience with these units?  Most
> flash memory is not designed for the long term repeated read/write/erase
> cycles of a primary disk drive -- how are these holding up?  Is the
> flash configuration totally transparent to the Linux file systems and
> formatting operations?
>
> Yasha Karant

I have no experience with these drives but I personally don't see any 
reason to use them.  I would far rather buy regular HD and then install 
more RAM in the system.  Excess RAM gets automagically assigned to cache 
by the kernel so even a relatively inexpensive RAM stick will give you a 
much faster and much smarter cache than a hybrid drive.

Here's an example from a small LTSP system I run:

Mem:  16233776k total, 16036304k used,   197472k free,   748100k buffers
Swap: 16777212k total,        0k used, 16777212k free, 12283660k cached

Note that there is essentially no free RAM but about 12 GB of cache :)

Jeff