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Connecting 1Gb and 2Gb transfer rates...

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Adam Hicks

Connecting 1Gb and 2Gb transfer rates...

I currently have two applications that are running on two servers (one application per server). Both servers share a common RAID
storage device.

I may be developing a third application in the future and would be running
the new application on a new Sever(and on a new RAID). I may want to connect the three servers (and the two RAID devices) together so that I can more easily perform a "manual failover" if the need ever arises.

My existing RAID device has a 1Gb transfer rate. It is my understanding that the new RAID devices have a 2GB transfer rate, and that there may be problems with linking a server to a 1Gb RAID and a 2Gb RAID at the same time. Do you all know what issues (if any) exist with having a 1Gb and a 2Gb
RAID on the same server? If there are problems, are there any "get-arounds" that would allow me to accomplish this?

Thank you very much for your time.
Tim Sanko
Trusted Contributor

Re: Connecting 1Gb and 2Gb transfer rates...

I am connecting to both a 2 GB raid
EMC 8530 and an EMC 4330 (Old number may not be correct). But one uses 2GB and old uses 1 GB connection. I have no problems using 2 GB's to them. The throughput never comes close to eating the bandwidth...

Ashwani Kashyap
Honored Contributor

Re: Connecting 1Gb and 2Gb transfer rates...

I think the spped of the channel will be equal to the slowest link in that channel .
Geoff Wild
Honored Contributor

Re: Connecting 1Gb and 2Gb transfer rates...

We are currently upgrading our SAN from 1GB to 2GB - during server migrations, we have them going through both the 1GB and 2GB SAN - no issues what-so-ever.

Our HBA's are 2 GB already and the FA's on the EMC DMX Frames are 2 GB as well - we have 2 Brocade fabrics - 1GB and 2GB.

You shouldn't have any issues with what you are intending...

If it is going to be permanent, you may want to place a Support call with HP - just to have their Engineers verify it.

Proverbs 3:5,6 Trust in the Lord with all your heart and lean not on your own understanding; in all your ways acknowledge him, and he will make all your paths straight.
Mike Naime
Honored Contributor

Re: Connecting 1Gb and 2Gb transfer rates...

Connecting all of this hardware together is what SANS are all about!

We have a mixture of 1GIG and 2GIG devices on our SANs. The big question here is going to be what is the speed of the SAN switch that you plug the new hardware into.

The 2GIG devices are smart enough that they will switch to 1 GIG mode if plugged into a 1GIG device. So, if you buy new storage and servers, and plug them into your existing 1GIG SAN switch, they will operate at 1 GIG.

I have all Compaq branded Brocade switches, and Compaq (HSG and EVA) storage.

I do have some ES47's with 2 GIG (DUAL) HBA's that are plugged into a 2 GIG switch. These are Zoned and Presented (SSP) to storage on both EVA and HSG storage controllers. The EVA is plugged into the same 2 GiG switch, and is accessed at 2GIG speeds. The HSG's are plugged into 1GIG switches, and are accesses at a 1GIG rate.

I also now have lots of 2GIG HBA's plugged into the old 1 GIG switches. (Gotta use up those free SAN ports!)

If you purchase a 2 GIG switch(s) and attempt to conenct it to your 1GIG switch(s), you will have to change the PID_MODE on the old switches to 1 before they will talk to the 2 GIG switches. Also be sure and set your DOMAIN ID's before you connect them.
VMS SAN mechanic