I think we are over subscribing the ports on our WS-X6548-GE-TX= (Catalyst 6500 48-port fabric-enabled 10/100/1000 Module) line cards in our 6509. This 6509 is the access layer for our servers which are being migrated from 100MB connections to gig connections.
We've been experiencing odd, random slow throughput problems with many of the servers and have uncovered the fact that these line cards have an 8:1 over-subscription rate to the switch fabric.
This has been confusing to troubleshoot because the interface counters don't show dropped packets. However in the document http://cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801751d7.shtml#ASIC, under the heading 'Connectivity Problem or Packet Loss with WS-X6548-GE-TX and WS-X6148-GE-TX Modules used in a Server Farm', it talks about disabling HOL, Head of Line blocking, and if there are any drops, they will move to the interface counters so we can find the culprits that are hogging the shared path to the fabric.
My question is, if we disable HOL, will this cause any interruption of traffic to the servers that is connected to that port? Or is this transparent to any traffic that is occurring?