On Thu, Jan 12, 2012 at 03:05:32PM +1100, Daniel Carosone wrote: > On Sun, Jan 08, 2012 at 06:25:05PM -0800, Richard Elling wrote: > > ZIL makes zero impact on resilver. I'll have to check to see if L2ARC is > > still used, but > > due to the nature of the ARC design, read-once workloads like backup or > > resilver do > > not tend to negatively impact frequently used data. > > This is true, in a strict sense (they don't help resilver itself) but > it misses the point. They (can) help the system, when resilver is > underway. > > ZIL helps reduce the impact busy resilvering disks have on other system
Well, since I'm being strict and picky, I should of course say ZIL-on-slog. > operation (sync write syscalls and vfs ops by apps). L2ARC, likewise > for reads. Both can hide the latency increases that resilvering iops > cause for the disks (and which the throttle you mentioned also > attempts to minimise). -- Dan.
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