[OmniOS-discuss] Slow performance with ZeusRAM?

[Bob Friesenhahn]

On Thu, 22 Oct 2015, Matej Zerovnik wrote:

> I’m using the default value of 128K on linux and OmniOS. I tried with recordsize=4k, but there is no different in iops…

There should be a large difference unless the file data is already 
cached in the ARC.  Even with caching, a block size of 128k means that 
128k is written to underlying store, although a useful purpose of your 
ZIL device is that an aggregation of multiple writes during the TXG 
interval to the same 128k block may be written as one write at the 
next TXG sync interval (rather than immediately).

Try umounting and re-mounting your zfs filesystem (or 'zfs destroy' 
followed by 'zfs create') to see how performance differs on a freshly 
mounted filesystem.  The zfs ARC caching will be purged when the 
filesystem is unmounted.

Do you have compression enabled for this filesystem?

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