iSCSI issues

  • 7 January 2014
  • 5 replies

Userlevel 4
Create Date: Feb 22 2012 9:51AM


I'm trying to setup iSCSI over an X670, between a Windows host and an Equallogic PS4100 array

The Equallogic box is connected on a single gig port via a 1000T SFP, the Windows box has an Intel X520 10gig card installed, using a 3m twinax cable. Both of those have jumbo frames enabled.

On the x670 I have "enable jumbo-frame ports all" set. I've created a new VLAN and untagged it on the ports for both units.

From the server I can ping the Equallogic unit, "ping -l 8000" works ok. When mounting an iSCSI volume and running Wireshark I can see lots of 'TCP Dup ACK', 'TCP Window Update' and 'TCP Retransmission' events, after a few seconds the drive hangs.

* Slot-1 LL_10G_STACK1.87 # show port 1:20,1:34 information 

Port      Flags              Link      ELSM Link Num Num  Num   Jumbo QOS     Load

                             State     /OAM UPS  STP VLAN Proto Size  profile Master


esxstg1_> Emj-----e--fMB---b active    - / -  6    0    1   1   9216  none    

eqlarr1_> Emj-----e--fMB---b active    - / -  1    0    1   1   9216  none


Any ideas? If I connect the Windows box up via a gig cable direct to the array the performance is fantastic.


(from nat_morris)

5 replies

Userlevel 4
Create Date: Feb 23 2012 12:55AM


whats the port state of these two ports (speed, duplex)?

Did you already checked the ports for errors?

Best regards


(from Falk_Fischer)
Userlevel 4
Create Date: Feb 23 2012 5:22AM

The ports duplex is ok, the Equallogic box is linked at 1000 full and the SFP+ cables are linked at 10G.

Previously the X670s were configured in a SummitStack with 2 SFP+ twinax cables between them (on ports 47+48), I've just wiped their configs and am giving it a go on a single standalone box.

(from nat_morris)
Userlevel 4
Create Date: Feb 23 2012 6:28AM

Just wiped the box, so it now only has 5 ports in use.

33 - Equallogic Controller A port 1, 1000T SFP

34 - Equallogic Controller A port 2, 1000T SFP

35 - Equallogic Controller B port 1, 1000T SFP

36 - Equallogic Controller B port 2, 1000T SFP

41 - Dell Server, Twinax SFP+

On Wireshark running on the server we see lots of TCP out-of-order, retransmission and window update messages.

Strange thing is, if I hook all 4 gigE ports from the Equallogic up to a Netgear gig switch, then a single gig cable from that to the X670 everything works well.

Any ideas? thanks!!

(from nat_morris)
Userlevel 4
Create Date: Feb 24 2012 3:42AM

These are the combinations that work and those that don't:

(from nat_morris)
Userlevel 4
Create Date: Mar 10 2012 10:57AM

What xos version are you using ?

And it might be that you see those out of sequence packets due to tcp /ip offloading on the servers nic card.

And what are the lacp /lag settings on the box ? (from Erik_Bais)