How to speed up slow zpool scrub?

[Bob Friesenhahn]

On Fri, 29 Apr 2016, Andrew Berg wrote:
>
> On a side note, ZFS uses lots of RAM for *caching*. Any corruption there 
> might affect your applications and/or system, but not your on-disk data. It's 
> also highly unlikely that you will have bad data written, but then never have 
> any bit flips on reads later. You *will* know something is wrong.

ZFS uses RAM for caching the pool and filesystem structures, and 
metadata.  If this data becomes correct, then innocent data may be 
overwritten with corrupted data because zfs made the wrong decisions. 
It is true that you are likely to soon know that something is wrong, 
but by then it may be too late.

For proper operation of ZFS one needs:

   o Reliable RAM

   o Reliable disk cache sync request

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/