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Posted by on August 22, 2005, 12:02 pm
Please log in for more thread options I manage a small network (75 desktops, 4 servers) with a single HP Procurve 4000m switch which has one 1-port gigabit module and the other 7 modules having ten 10/100 ports. I've got two HP Proliant DL servers with dual gigabit NICS. Obvioulsy, with only one gigabit port, I can only hook one of the NICS on one of the servers to it. What I'm thinking of doing is purchasing a separate smaller Linksys 16 port gigabit switch (under $400) so I can team the dual NICS on both of the proliant servers to get 2GB on each. FWIW, the two servers are a terminal server which hosts about 15-20 users (currently dual NIC'd at 200 Mbps), and our main database/file/print server (only one NIC at 1GBps) which sees some pretty heavy use. Both are win2k. My questions, therefore, are: 1) I'm guessing I can plug the Linksys into the Procurve through the gigabit port, correct? Should I be using a CAT 6 cable for this or will CAT 5e do? If this is not how I would hook this up, what are the options? Should I take the cable coming from the router/firewall and plug it into the Linksys, then plug the Procurve into the Linksys? 2) Since the Linksys is a managed switch I could configure Port trunking. Is this something that should always be done when setting up dual NICS (primary goal is load balancing with lesser emphasis on fault tolerance)? I tried port trunking when configuring dual 100 NICS on the terminal server, but saw no readily apparent benefit. HP Procurve has told me different stories each time I've called them. 3) Will this scenario actually give me noticeable improvements? I don't want to invest even a little bit of money if improvements are minimal. Thanks for any insight into this. Brian | |||||||||||||||||||||||||||||||||||||||||||
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Posted by Al Dykes on August 22, 2005, 3:12 pm
Please log in for more thread options I think with the right 100MB cards in a server it can be bandwidth aggregated to use two or three cards. Never done it, though. I'd avoid an unmanaged switch in any production environment, especially one with a non-trivial topology. With "only" 75 desktops I'd be suprised if you are bandwidth-limited on more than one server. Learn to use the management screens in your 4000m (a nice box) to see what your traffic is. When you find your busy server use perfmon on it to see what it's bottlenecked on. -- a d y k e s @ p a n i x . c o m Don't blame me. I voted for Gore. | |||||||||||||||||||||||||||||||||||||||||||
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Posted by J. Clarke on August 22, 2005, 4:57 pm
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bpanders71@hotmail.com wrote: > I manage a small network (75 desktops, 4 servers) with a single HP
> Procurve 4000m switch which has one 1-port gigabit module and the other > 7 modules having ten 10/100 ports. I've got two HP Proliant DL servers > with dual gigabit NICS. Obvioulsy, with only one gigabit port, I can > only hook one of the NICS on one of the servers to it. What I'm > thinking of doing is purchasing a separate smaller Linksys 16 port > gigabit switch (under $400) so I can team the dual NICS on both of the > proliant servers to get 2GB on each. Read the specs carefully. If you're talking about the SRW2016, there's no mention of either 802.3ad or Fast Etherchannel, and I can't imagine a Cisco product supporting any other variant of aggregation if it doesn't support those. > FWIW, the two servers are a
> terminal server which hosts about 15-20 users (currently dual NIC'd at > 200 Mbps), and our main database/file/print server (only one NIC at > 1GBps) which sees some pretty heavy use. Both are win2k. Are you looking for performance or fault tolerance? If you're looking for performance, the first thing to consider is that you're still only going to have a 1 Gb pipe from the second switch into the Procurve, so unless you're encountering high traffic between servers you're not going to gain anything. You'd at the minimum need to put a second gigabit port in the Procurve. Next, Terminal Services can run fine over a dialup line. 20 sessions under worst case conditions are still getting 5 MB/sec out of 100TX--you're not going to see much gain giving that server more bandwidth unless there's something you're not telling us. Next, what transfer rate do you get out of your file/print/database server now? Filling even a 1 GB/sec pipe more than momentarily takes an exceedingly heavy duty server and if it's to be done steady state on disk access you need rather massive storage system. If you're going for fault tolerance, then you're back to the single link between the second switch and the Procurve, so you don't really gain anything. If you really want aggregation, you'd do better to put three more gigabit ports in the Procurve, which will cost you about $1000. > My questions, therefore, are:
> > 1) I'm guessing I can plug the Linksys into the Procurve through the > gigabit port, correct? Should I be using a CAT 6 cable for this or > will CAT 5e do? Yes, generally speaking any 1000TX device can be connected to any other in the manner you describe. Generally speaking CAT5E is adequate for 1000TX--it was _designed_ for CAT5, 5E nails down some numbers that most existing CAT5 meets but was never tested for, and one of the gigabit vendors demonstrated at a trade show that it can run error-free over 8 strands of barbed wire. If it's not running properly on CAT5E and there's no unusual source of EMI then something is broken. > If this is not how I would hook this up, what are the
> options? Should I take the cable coming from the router/firewall and > plug it into the Linksys, then plug the Procurve into the Linksys? No reason to use a gigabit port for the router unless you've got an unusual situation--most small businesses have at most 3 Mb/sec or so access. > 2) Since the Linksys is a managed switch I could configure Port
> trunking. Is this something that should always be done when setting up > dual NICS (primary goal is load balancing with lesser emphasis on fault > tolerance)? I tried port trunking when configuring dual 100 NICS on > the terminal server, but saw no readily apparent benefit. HP Procurve > has told me different stories each time I've called them. No. What you seem to be trying to do is called "aggregation", not "trunking" (although sometimes aggregation is referred to as trunking for some reason). If you are looking for load balancing and fault tolerance then aggregation is what you need to use. > 3) Will this scenario actually give me noticeable improvements? I
> don't want to invest even a little bit of money if improvements are > minimal. Based on what you've said so far it seems unlikely. > Thanks for any insight into this.
> Brian -- --John to email, dial "usenet" and validate (was jclarke at eye bee em dot net) | |||||||||||||||||||||||||||||||||||||||||||
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Posted by on August 23, 2005, 12:03 pm
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Thanks for all the help and suggestions. Based on what everyone is saying it sounds like I'd probably be better off to purchase three more gigabit modules for the Procurve, which would displace 20+ other ports, but then perhaps I could just get a standard 10/100 switch to handle those. I really don't know how much bandwidth these servers are eating up, but in my wierd way of thinking thought that if I opened up the pipe a bit it might allow for better traffic to the server. We have a touchy DB app that frequently crashes and I figured if there was a bottleneck causing the issue, a gigabit switch might help things out. Thanks- Brian | |||||||||||||||||||||||||||||||||||||||||||
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Posted by Walter Roberson on August 22, 2005, 7:30 pm
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:I manage a small network (75 desktops, 4 servers) with a single HP :Procurve 4000m switch which has one 1-port gigabit module and the other :7 modules having ten 10/100 ports. I've got two HP Proliant DL servers :with dual gigabit NICS. Obvioulsy, with only one gigabit port, I can :only hook one of the NICS on one of the servers to it. What I'm :thinking of doing is purchasing a separate smaller Linksys 16 port :gigabit switch (under $400) so I can team the dual NICS on both of the :proliant servers to get 2GB on each. FWIW, the two servers are a :terminal server which hosts about 15-20 users (currently dual NIC'd at :200 Mbps), and our main database/file/print server (only one NIC at :1GBps) which sees some pretty heavy use. Both are win2k. I'd think it likely that that plan is headed for trouble. :My questions, therefore, are: :1) I'm guessing I can plug the Linksys into the Procurve through the :gigabit port, correct? Should I be using a CAT 6 cable for this or :will CAT 5e do? Cat5e will do, at least for moderate distances. :2) Since the Linksys is a managed switch Could you check that again? Last time I checked about 3 months ago, the least expensive *managed* gigabit switch I could find was about $1000. The $400 Linksys switches were NOT managed at the time. :I could configure Port :trunking. Is this something that should always be done when setting up :dual NICS (primary goal is load balancing with lesser emphasis on fault :tolerance)? Port trunking? As in putting in multiple 802.1Q VLANs? That's not going to help fault tolerance: if your fault tolerance is MAC based then the MAC in the other VLAN would not be visible; if your fault tolerance is IP based then the two ports would have to be in different subnets in order to be able to select the proper port during normal operations. : I tried port trunking when configuring dual 100 NICS on :the terminal server, but saw no readily apparent benefit. Do you perhaps mean port aggregation? Port aggregation depends on the algorithm being used to distribute the packets between the available links. I don't recall which algorithms the Procurves have available. Often the algorithms are based upon taking the last N bits (2^N >= number of aggregated ports) of the source
or destination and using that as the link index; sometimes the source
and destination bits are xor'd. Unless you have configured per-packet load balancing on your aggregation ports (I -seem- to recall seeing that the Procurve could do that), the result is that any one source + destination MAC pair will always use the same link. Aggregating N ports does not get you N times the bandwidth (unless per-packet): instead it gives you opportunities to parallelize up to N different streams. Like a multilane highway: your car can't drive at 180 miles per hour just because there are three lanes, but 3 cars can independantly drive at 60 miles per hour on the three lanes. :3) Will this scenario actually give me noticeable improvements? I :don't want to invest even a little bit of money if improvements are :minimal. If you are expecting heavy traffic over the gigabit ports, then chances are that you will be disappointed with the $400 Linksys. On the consumer gigabit devices, the aggregate throughput supported is usually fairly low. Many of the consumer gigabit devices use the same chipset, so you pretty much have to take a jump in price class in order to get serious simultaneous bandwidth. Something like a Cisco Cat2960 perhaps; I imagine others will pitch in with other reliable high-throughput devices. [Note: there have been some reports of bad experiences with Netgear's line of managed gigabit switches, which look nice on paper...] -- Look out, there are llamas! | |||||||||||||||||||||||||||||||||||||||||||
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>Procurve 4000m switch which has one 1-port gigabit module and the other
>7 modules having ten 10/100 ports. I've got two HP Proliant DL servers
>with dual gigabit NICS. Obvioulsy, with only one gigabit port, I can
>only hook one of the NICS on one of the servers to it. What I'm
>thinking of doing is purchasing a separate smaller Linksys 16 port
>gigabit switch (under $400) so I can team the dual NICS on both of the
>proliant servers to get 2GB on each. FWIW, the two servers are a
>terminal server which hosts about 15-20 users (currently dual NIC'd at
>200 Mbps), and our main database/file/print server (only one NIC at
>1GBps) which sees some pretty heavy use. Both are win2k.
>