S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
20-53
Cisco MDS 9000 Family Troubleshooting Guide, Release 3.x
OL-9285-05
Chapter 20 Troubleshooting IP Storage Services
iSCSI TCP Performance Issues
iSCSI Node name is iqn.1987-05.com.cisco:02.75af2f95624c.shark-nas
iSCSI alias name: SHARK-NAS
Node WWN is 20:00:00:0c:30:57:5e:c2 (dynamic)
Member of vsans: 777, 778
Number of Virtual n_ports: 1
Virtual Port WWN is 20:00:00:0c:30:57:5e:c2 (configured)
Interface iSCSI 2/1, Portal group tag is 0x1001
VSAN ID 0, FCID 0x 0
No. of FC sessions: 1
No. of iSCSI sessions: 1
iSCSI session details
Target node:
Statistics:
PDU: Command: 0, Response: 0
Bytes: TX: 0, RX: 0
Number of connection: 1
TCP parameters
Local 10.48.69.250:3260, Remote 10.48.69.233:1026
Path MTU: 1500 bytes
Retransmission timeout: 300 ms
Round trip time: Smoothed 150 ms, Variance: 31
Advertized window: Current: 998 KB, Maximum: 1000 KB, Scale: 4
Peer receive window: Current: 1000 KB, Maximum: 1000 KB, Scale: 4
Congestion window: Current: 12 KB
VSAN ID 777, FCID 0x610001
No. of FC sessions: 1
No. of iSCSI sessions: 1
iSCSI session details
Target node: shark_nas
Statistics:
PDU: Command: 392051, Response: 392042
Bytes: TX: 25692593152, RX: 0
Number of connection: 1
TCP parameters
Local 10.48.69.250:3260, Remote 10.48.69.233:1057
Path MTU: 1500 bytes
Retransmission timeout: 300 ms
Round trip time: Smoothed 2 ms, Variance: 1
(Watch out for these numbers. The output is for a TCP session that goes only through one Gigabit
Ethernet switch. When there are multiple router hops, as well as WAN links in the middle, the RTT will
grow, and the variance will fluctuate with higher values. You may need to adjust the retransmission
timeout.)
Advertized window: Current: 1000 KB, Maximum: 1000 KB, Scale: 4
(This is the window size set on the Windows client. See
Figure 20-14
.)
Peer receive window: Current: 1000 KB, Maximum: 1000 KB, Scale: 4
(This is the window size set on the IPS iSCSI interface. See
Figure 20-14
.)
