[OmniOS-discuss] Debating Swapping 2TB with 4TB drives in RaidZ2 or Create new Vol and clone

[Bob Friesenhahn]

On Fri, 21 Mar 2014, Matthew Mabis wrote:

> I know the drive itself does 512b emulation but i would rather run 4K if theres a performance increase!

Does Illumos really have a "4k" path?  It is my impression that 
knowledge of "4k" influences offsets and allocated block sizes but 
that otherwise things are really still done in terms of 512 byte 
sectors.

A drive which can only support I/O in 4k sectors would not be very 
usable on most systems.

Regardless, I can not imagine why someone would want to replace 2TB 
drives with 4TB drives.  The resilver rate is no better with the 4TB 
drive than with the 2TB drive so the time to resilver is doubled and 
there are limits to what is tolerable.  I/O performance would not 
improve and in fact it may diminish with the larger drives.  It is 
much better to add more spindles to the pool (i.e. another raidz2 
vdev).

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