> I'm unclear on the best way to warm data... do you mean to simply `dd
> if=/volumes/myvol/data of=/dev/null`?  I have always been under the
> impression that ARC/L2ARC has rate limiting how much data can be added to
> the cache per interval (i can't remember the interval).  Is this not the
> case?  If there is some rate limiting in place, dd-ing the data like my
> example above would not necessarily cache all of the data... it might take
> several iterations to populate the cache, correct?

Quick update... I found at least one reference to the rate limiting I was
referring to.  It was Richard from ~2.5 years ago :)

I assume the source code reference is still valid, in which case a
population of 8MB per 1 second into L2ARC is extremely slow in my books and
very conservative... It would take a very long time to warm the hundreds of
gigs of VMs we have into cache.  Perhaps the L2ARC_WRITE_BOOST tunable
might be a good place to aggressively warm a cache, but my preference is to
not touch the tunables if I have a choice.  I'd rather the system default
be updated to reflect modern hardware, that way everyone benefits and I'm
not running some custom build.
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