Dell PowerVault TL4000 - Manual (Page 41)

Troubleshooting
Dell Model TL24iSCSIxSAS 1Gb iSCSI to SAS User’s Guide Rev.C Page 39
Note: If you can “ping” the bridge but the GUI interface fails to appear check
the setting within the Web Browser you are using. If you are directly
connected to the bridge then any proxy setting will require adjustment
and may require you to contact your administrator.
• Ensure that the CHAP settings for the initiator and the bridge are the same.
Note: A common mistake is to enable CHAP only for a device after the initial
discovery by the initiator. It will be necessary to remove the address
from the discoveries tab and recreate it with the appropriate CHAP
settings, otherwise any rediscoveries will be attempted without CHAP
and no devices will be returned.
• Force a rediscovery from the initiator.
• Reboot the library and bridge.
• If none of the above resolves your problem, please contact support.
10.3 Poor Performance
• Poor performance can be caused by many different reasons. The following checklist is provided as a
guide to where you may find ways to improve performance.
• Ensure your initiator and bridge are communicating at the fastest possible network speed. Within the
GUI interface in the Network Connections window, select this and check the Link Speed entry in
each of the Link Status Box. This should be 1000Mb/s - if this is 10 or 100Mb/s this will limit the
performance dramatically.
• Packet loss can be a cause of poor performance. Within the Link Status Box check the number of TX
and RX errors for both network interfaces. This should be zero or, a very small number. If these are
showing a large number of errors, check the connections between the bridge and the initiator. Also
check that the entire network cabling between the initiator and the bridge is Cat5e certified.
• By enabling Jumbo packets (increasing the MTU size to 9000 from within the GUI Network
Connections window) you can improve the throughput performance of the bridge. This will only work
if ALL of the components in the infrastructure between the Initiator and the bridge are enabled for
Jumbo packets. That includes the HBA, all switches and routers and the bridge itself. If any of the
components are not enabled or not capable of handling Jumbo packets then unexplainable packet
loss or corruption can happen.
• Data Digests are an extra level of checksum error checking on top of the standard TCP/IP checksum
error checking (configured on the initiator). However, the calculation of these extra checksum can
greatly effect the overall performance. Therefore, Header and Data Digests should only be enabled
where the integrity of the Network connection is in doubt.
• It is possible to configure the bridge so that the data from the initiator is balanced across both
network connections. Ensure that you have connected and configured them in accordance to
Appendix C and not by enabling the Multipath connection option in the Windows initiator login
screen. You should also check the routing tables in your switches, routers and initiator to ensure
both IP-addresses are not routed down on Network link at any stage.
Also, add the following registry settings:
From the start menu within windows, select run, then type regedit.
In the folder: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\