We are buiding a MAN between our major sites GE links and 6509/sup720-10GE with WS-X6724 SFP cards.
SAN traffic will be a major user, and has some unique qos requirements. (SAN devices are IBM SVC replictors using FC/IP)
- It is drop sensitive ... ie it reacts very badly to dropped packets
- It is not jitter sensitive
- It will use all the bandwidth we can give it... and can easily starve other applications
So we have to both protect the SAN traffic, and also protect others from it.
I'm looking at ways to implement the queuing on the 6724 cards and am considering dedicating one of the 6724 tx-queues just for SAN.
ie .. something like ...
- Priority queue 25%
- High Priority Applications 15 %
- SAN 30%
- Regular Traffic 30 %
Doing this means we can't have a dedicated scavenger queue, and would need to use low thresholds within the 'regular traffic' queue for that.
How have others done this? What did you do for wrr queue thresholds, sizing and servicing ratios?
Thanks in advance