Which MDS 9140 ports are recommended to connect a Clariion CX4 ?

Lots of questions and I'm not sure about a few, but I know the first 8 ports are non blocked (non oversubscribed), so that means each port has dedicated bandwidth. Ports 9-40 share their bandwidth. I'd put storage arrays on the first 8 ports and hosts on the remaining 9-40 ports. As for buffer req's, each port can accomodate storage as well as hosts, as long as they're reasonably closeby (multi mode, within a few hundred meters).

Is the 9140 still supported ? It's a rather old switch, isn't it ? It's 9124, 9134 and 9148 (new new new) nowadays in the 91xx range (for 3 years or so already).

Thanks for the quick answer RRR.

I have looked deepr into the buffercredits on 9140 from Cisco's papers.

We can read :  "Up to 255 buffer credits for target-optimized ports (ports1 to 8) and 12 per host-optimized ports (ports 9-40).

So, it is not possible to 'transfer' buffer credits from th eight first ports to ports 9-40, which have a default of 12 BC's.

I think you're right, it is best to connect the storage on one of the 8 first ports and the same for long distance ISL's.

Your oversubscription adevice is right as well.

The 9140 is an old switch, out of sales from 2007 I think.

Probably if new switches need to be added, it would be the ones you mention. 9124 is also old...

Thanks again.

Jack

MDS9124 is still a current model, so you should be safe there

Hi back RRR, thanks for your feedback. Sorry but the scope has changed after some internal meetings.

I have been rethinking the architecture and finally, it could be that I can recuperate two 9140 switches to move to another room. This will be done "temporary", because the goal to renew the whole SAN in a couple of years, and as I have about 17 MDS switches, I want to do all at the same time.

After a deep analysis of the used/free ports , it is possible (on paper...) to swap used ports from two switches to some others. I also have a 'spare' MDS 9140 available.

I have to take care, because I have several VSANs, but this is OK.

Now, two new questions arise :

• When those two 9140 will be empty, does anuyone know how I can "clear" all the config from the switches so when I move them to the other room, I can merge them easily ?

I'm used with the Brocade's, where I can run a "clear" command.

• Regarding ISL's, can I use regular ports (ports 9-40 with 12 buffer credits) for "internal" ISL's. With internal ISL's, I mean ISL's between two switches in the same rack/room. Then one of these switches will be ISL'ed to other switches in further locations (several kilometers), where I will be using the ports 1-8 for long distance ISL's. I presume that ISL'ing in the same location does not require as hig buffer/subscription as long distance ISL's...

Thanks for your inputs.

Regards.

Jacky.

1) "write erase" will clear existing configuration, after running that command i typically run "reload" and begin configuring basic configuration

2) can you put those ports in "dedicated" mode ? Because they need to be in dedicated mode to be type "E or TE". If you can set them to dedicated mode i don't see why they can't be used for ISLs.

Thanks for the answers dynamox.

OK for 1.

For 2., I think this should be possible as you tell (dedicated mode). But I think that the ports 9-40 should not be used for long distance ISL's, am I wrong ?

Any extra advice is still welcome.

Jack

you probably right, we had to get at least a 9222i because it has more buffer credits for long distance connectivity.

Hi back all, to be sure I understand correctly...the initial question still applies.

dynamox suggests to connect the storage ports on the first 8 ports opf the MDS 9140.

But as the CX4 will be connected locally (I mean, in the same rack as the switches), is this mandatory ?

Of course, other hosts from other remote switches (long distance) would connect ot this storage, but then I will use ports 1-8 for the ISL's.

Regarding the "normal" ISL's, i.e., the ISLs from switch to switch in the same rack, can we use ports 9-40 without problem ?

Look at the diagram below : both switches are mounted in the same local rack :

Not sure the ISL need to be connected to ports 1-8 absoultely. Any idea ?

For long distance, we agree; ports 1-8 should be used.

Any extra advice is welcome.

Regards.

Jack

I believe on the 9140 each set of 4 ports outside of 1-8 are considered a port group (you can see the grouping by right clicking on the switch and clicking over subscription). In these gen 1 switches they share 2.5 Gbps bandwidth. If you were to use one of these as an ISL, in dedicated mode, you would need to put the remaining 3 ports in out-service mode. If you used them for storage you would have the ability to leave them in shared mode. Just know that each connection in that port group will compete over that 2.5 Gbps.

I don't think the distance between the two devices really comes into play here. Think about how fast light really travels. Going 100 meters vs 1 meter isn't doesn't eally add time. Your delays will be within the switches and other devices.

How many storage and ISL ports are you looking to accommodate per switch?

Yeah it does look like you are running low on ports there.

I agree when we start talking kms we start to add noticably latency to a link. In either case an ISL in ports 1-8 should not act any different then an ISL in ports 9-40 since it will have dedicated bandwidth and the correct number of buffer credits.

Am correct in that if you wanted to using 1-8 on switch02 you would need to move one of those F ports to a shared port? Is that a possiblity so that you can use one of those prots for the extra ISL?

Hi hersh, thanks so much for your reply. Sorry for my late reply, I was abroad during the last days.

Regarding a possible move of some F ports from switch2 and ports 1-8, if someone can confirm me that I can use ports 9-40 to connect the ports of a CX, this should be possible. For example, from switch2, I could move port1 (CX700 SP port) to port 22 and port5 (CX700 SP port) to port 37, so I have two free ports on 1-8 to connect a new switch (ISL's).

Regards.

Jack