PowerVault documentation question re: flow control

Question

Under the 'iSCSI network rules' section of https://www.dell.com/support/manuals/en-us/powervault-me5084/me5_series_sm/me5-series-storage-system-rules?guid=guid-3e9e84a0-66b9-4df8-bd6b-13461a338c9b&lang=en-us it recommends that flow control should be 'enabled for both sending and receiving on all switch ports and server NIC ports.'   However, under the 'Ethernet switch specification recommendations for iSCSI traffic' section of https://www.dell.com/support/kbdoc/en-ca/000201155/me5-troubleshooting-iscsi-controller-ethernet-port-link-down it only mentions enabling receive-side flow control (i.e. not transmit).   Similarly, the same document says that PowerVault ME switch configurations are similar to the configurations for SC series arrays, and the SC switch configuration guide (https://dl.dell.com/manuals/common/dell-emc-networking-s5148f-on-scg-sc-ps-series-scg3928.pdf) says to turn transmit flow control off (with receive on).   Which is correct? Should we have flow control for both transmit and receive turned on for each switch port handing iSCSI, or just receive?

DELL-Charles R · Answer

Hello,

The first link you posted is the one is the one you should use.

From the Support Matrix: ME5 Series storage system rules:

If the iSCSI initiators are connected to ME5 Series storage systems through the network switches, ensure that your switches support IEEE 802.3x flow control, and the flow control is enabled for both sending and receiving on all switch ports and server NIC ports

I hope that helps.

DB_2022 · Answer

Thanks for the reply. Out of curiosity, why is the Support Matrix document considered 'more authoritative' than the ME5 troubleshooting document?

DELL-Charles R · Answer

Hello,   I don't know about which one is more authoritative. I can say the information I provided, concerning flow control, was from one of our Storage Engineers.

PowerVault

Was this post helpful?