On Feb 16, 2013, at 3:59 PM, Sašo Kiselkov <[email protected]> wrote:
> 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). Flow control is logged in kstats for most NICs (kstat -n statistics) Unfortunately, there is no consistent statistic name across NIC drivers. For example, e1000g uses statistics XOFFs_Xmitd and XOFFs_Recvd to count flow control packets. -- richard > > Cheers, > -- > Saso > > _______________________________________________ > OpenIndiana-discuss mailing list > [email protected] > http://openindiana.org/mailman/listinfo/openindiana-discuss -- ZFS storage and performance consulting at http://www.RichardElling.com _______________________________________________ OpenIndiana-discuss mailing list [email protected] http://openindiana.org/mailman/listinfo/openindiana-discuss
