Hello, On Mar 5, 2010, at 10:46 AM, Abdullah Al-Dahlawi wrote:
> Greeting All > > I have create a pool that consists oh a hard disk and a ssd as a cache > > zpool create hdd c11t0d0p3 > zpool add hdd cache c8t0d0p0 - cache device > > I ran an OLTP bench mark to emulate a DMBS > > One I ran the benchmark, the pool started create the database file on the ssd > cache device ??????????? > > > can any one explain why this happening ? > > is not L2ARC is used to absorb the evicted data from ARC ? No, it is not. if we look in the source there is a very good description of the L2ARC behavior: http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/fs/zfs/arc.c "1. There is no eviction path from the ARC to the L2ARC. Evictions from the ARC behave as usual, freeing buffers and placing headers on ghost lists. The ARC does not send buffers to the L2ARC during eviction as this would add inflated write latencies for all ARC memory pressure." Regards Henrik http://sparcv9.blogspot.com
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