On 09/25/2012 09:38 PM, Jim Klimov wrote:
> 2012-09-11 16:29, Edward Ned Harvey
> (opensolarisisdeadlongliveopensolaris) wrote:
>>> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
>>> boun...@opensolaris.org] On Behalf Of Dan Swartzendruber
>>> My first thought was everything is
>>> hitting in ARC, but that is clearly not the case, since it WAS
>>> gradually filling up
>>> the cache device.
>> When things become colder in the ARC, they expire to the L2ARC (or
>> simply expire, bypassing the L2ARC).  So it's normal to start filling
>> the L2ARC, even if you never hit anything in the L2ARC.
> Got me wondering: how many reads of a block from spinning rust
> suffice for it to ultimately get into L2ARC? Just one so it
> gets into a recent-read list of the ARC and then expires into
> L2ARC when ARC RAM is more needed for something else, and only
> when that L2ARC fills up does the block expire from these caches
> completely?
> Thanks, and sorry for a lame question ;)

Correct. See
for an exact description of the ARC<->L2ARC interaction mechanism.

zfs-discuss mailing list

Reply via email to