Re: RAM-only caches

Terence Kelly wrote:

> Do RAM-only caches make sense?

In some configurations and locations yes, but at most locations probably
in combination with disk based caches. With the current trend on
bandwidth increases and memory prices I'd say for most people a memory
only cache is not (yet) economically feasible, but on the other hand,
disks have great trouble to keep up with the bandwidth increases.

> If so, how large would they be? Are we talking 100MB - 1GB, or
> much larger?

MB is probably not a good measure when estimating this as the scales are
ever changing. My guess on what size is feasible is somewhere in the
range 1 to 6 hours worth of traffic, depending on wallet size and cache
use/location of course.

Intelligent use of main memory cache can remove a great deal of the disk
strain seen in most caches today (and squids current I/O pattern is
extreme, hard to get any worse), allowing hybrid caches to sustain a
much higher rate. Todays disks are fast on large linear data transfers,
but very poor on random I/O.

--
Henrik Nordstrom
Spare time Squid hacker