Cisco 2960G and HP Multifuntion NIC performance

[lars.molstad]

Hi folks

We have a small datacenter with lots of 2960G's as access-switches and a 4510R as a aggregation switch.

Performance is relatively good, but after new HP servers with the HP Multifunction adapter seems slow when connected to 2960G's. The performance problem is not consistent as some servers have ~1G speed to the HP server, but others vary between 10 and 200Mbit. All other servers reach ~1G between each other, so there is no duplex problems involved. All servers connected to the same switch as the HP seems to have ok speed's but when the 4510R is involved in switching beetween the HP and other servers, it seems to be a speed problem between some servers. When connecting the HP to a port in the 4510R everything seems OK.

Anyone heard of a problem like this? "Everything" has been tested, cables, software (relatively new)..

L@rs

[lgijssel · Accepted solution]

Depending on the type of blades used in the 4510 and the way the uplinks are connected, there may be a considerable overbooking in the paths between servers.

I believe the backplane of the 4510 does something like 6Gig per slot. (may depend on the supervisor, I did not re-check)

This can easily be saturated via a 48-port gigabit module.

regards,

Leo

[lars.molstad]

Thanks.. I installed a 3750E between the access-switches and the 4510R and that solved all my network trouble.. Just to discover that we also have trouble with SAN performance....

L@rs

[corey]

Depending on what line cards you use there are a considerable number of issues with the specific bandwidth of the WS-X4548 and other GigE modules in the 45xx.

Look here for some clues:

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/hardware/module/guide/03instal.html#wp1037611

GigE flow control is big key as is spreading traffic among ports that are not oversubscribed heavily. (every 8 ports in a 45xx GigE 48 port card shares a single 1Gbps feed to the backplane)

Also there is a serious DBL (only if you have it enabled) performance bug in v12.2(31)SGA and above that will throttle throughput down to 10-25% of what it should be. If you are not using it, never mind. If you areusing it, and at 12.2(31) or above try turning it off. Bug ID is CSCsk07525.