[OpenIndiana-discuss] ISCSI SSD Performance

[Sašo Kiselkov]

On 02/17/2013 12:52 AM, Grant Albitz wrote:
> Yes jim I actually used something similar to enable the 9000 mtu that's why I want familiar with the config file method.
> 
> dladm set-linkprop -p mtu=9000 InterfaceName
> 
> 
> Flowcontrol is currently off on the zfs host but enabled by default on esxi,

This actually could be it - iSCSI uses TCP and if the ESXi host is
having trouble keeping up, it might be trying to get the OI host to slow
down by sending it TX pause frames. If the OI host ignores them and
continues firing iSCSI packets at full, the ESXi host will drop some of
them, which will trigger TCP's retransmission - this introduces latency
bubbles and significant performance penalties (even mild packet drop can
wreck havoc on a TCP link's throughput).

Cheers,
--
Saso