Fibre Channel (SAN)

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New Contributor
Posts: 4
Registered: ‎03-17-2008

SAN Replication

Hello,

Sorry for my bad english, We need some help because we are planning to implement a DR and we are with some problems regarding the SAN Replication.

We have an IBM storage solution that uses 2 brocade’s fiber switch model 2498-B40 (5100) at firmware 6.3.2b.
We have 2 datacenters but they are at the same building one at the 7 floor and the other on the 4 floor. We have more than 40 fibers directly connected.
We are going to take one of this datacenters and take it to 15 km away from the other.

We already negotiate the circuit 1gb dark fiber to connect the 2 brocade’s 2498-B40. I try a simple test on the circuit using one pc with hba on one site connecting to one switch on the other site but we cannot have light on the fiber.

We appreciate you help if it’s possible, to understand if we have to get some specification on the circuit side or if we have to get some special gbic for this to work or some king of firmware upgrade.

Can you please help us on this situation.

Regular Contributor
Posts: 164
Registered: ‎05-11-2011

Re: SAN Replication

Hi,

which SFP-Type and what type of fibers you are using (MM or SM)?

In you origing 2-Floor configuration i think you have MM-Fibers (OM1/OM2 or OM3) and 850nm SFP's.

Those SFP's are able to meet distances between 300m (OM1-Cable), 500m (OM2-Cable) and 860m (OM3-Cable) with 1Gbps.

When you now have 15km dark fiber, this should be an Single-Mode Fiber. So here you need different SFP (with 1310nm or 1550nm).

In addition you have to install the Brocade Extended Fabric Licences for distances beyond 10km.

Otherwise you can not allocate enough BB-Credits for this link.

Regrads

Ralf

Kind Regards
Ralf
New Contributor
Posts: 4
Registered: ‎03-17-2008

Re: SAN Replication

Hello,

Thanks for your reply, you're right we are using 850nm SFP's with OM3 fibers, so you are saying that we will need new SFP's to this solution to work? Just one more thing regarding to the licensing we have license for 8 Gib FC, Enhanced Group Management, Second Ports on Demand License - Additional 8 port Upgrade, Full Ports on Demand - Additional 16 port upgrade, fabric watch and fabric, do we need another addicional license? You mention Extended Fabric Licences?

Another thing was that we ask the provider for the fiber to be multi mode, is there any problem with that, is supposed to be Single mode?

I will not close this message for now but You where very helpfull. Thanks

Valued Contributor
Posts: 931
Registered: ‎12-30-2009

Re: SAN Replication

For long distance you can only use SM cabling and SFP's, the MM signal degrades to fast to reach the other end.

MM can at best get you approx. 500M depending on the speed your using.

So as ralf.schlosser said before

When you now have 15km dark fiber, this should be an Single-Mode Fiber. So here you need different SFP (with 1310nm or 1550nm).

He also mentioned

In addition you have to install the Brocade Extended Fabric Licences for distances beyond 10km.

Otherwise you can not allocate enough BB-Credits for this link.

On default settings a switch has only enough Credit Buffers to reach a distance of 10KM.

If you wish to go further you need the license, which enables you too reserve more buffers on the E-ports.

You can try it with less buffers but you could end up with underutilizing your ISL's. Should that be of no concern to you, omit the license.

Mind you should you buy the license, you need to buy it on/for every switch participating on the long haul ISL's

New Contributor
Posts: 4
Registered: ‎03-17-2008

Re: SAN Replication

Thanks for your reply

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