P4500 Multisite - FailOver Manager over Wireless

[Jared Plaisted]

Hi i have a customer with a multisite setup 2 nodes at each site (primary and secondary), currently running the Fail Over Manager at the Primary site.

The question came up about moving the FailOver Manager to a 3rd site connected via 54MBs wireless.

As far as FoM network requirements go I just assumed that it would be the same requirements as the storage nodes i.e atleast 1GB with less than 2ms latency.

I could not find any HP/Lefthand documentation that specifically mentions the network requirements for the FoM, can anyone confirm if a wireless link would be sufficient for the FailOver Manager.

Many thanks.

Jared

[Bryan McMullan · Accepted solution]

You would want a low latency, high reliability connection.  While a wireless connection may work, it is not optimal, nor I believe recommended.

[Jared Plaisted]

Pretty much as i thought also. Thanks.

[Bart_Heungens]

Hi,

Can't find the document for the moment but I read somewhere that the FOM is satisfied with 10Mb connection...

Since the FOM does not hold any data on it, it does not need the same specs as the storage nodes...

However, for the wireless aspect I would think about the stability of the connection... There are too much other factors that can have a bad influence on the connection...

Kr,

Bart

[David_Tocker]

How are you going to make sure you have independent paths to the wireless site? If you L2 bridge them you may be in trouble? Sounds like a bad idea to me unless you are going to run a separate network -

I.E.   (primary site 192.1.x.x --- FOM 192.168.2.x ---- secondary site 192.168.3.x) with routing between the sites....

Obviously you will need wireless routers rather than just bridging it into one big L2 domain.

You could use l3 switches and have separate interfaces talking to one big L2 domain, this should work equally well.

Good luck! Make sure if it is a simple network that you have power protection on the FOM! It is going to be the key to not loosing quorum....

[David_Tocker]

I guess I should make this a bit more clear. The important part about the FOM is that it does not loose connectivity to the two sites before they loose connectivity to each other. It is there to maintain quorum so therefore its connection to the two sites should be at least as robust as the link between them. Make sure you use high quality wireless gear - a possiblity for those on a budget could the the microtik gear with two seperate wireless cards talking to two seperate endpoints on each network. HP and Cisco both have appropriate gear but you may find budgetary issues rule them out. Your suggestion has actually given me a couple of ideas for our own setup... Keep in mind that it does not matter if the FOM falls offline unless the two sites loose connectivity - if they all loose connectivity you could be in a very difficult place - and in my experience HP support is very available until you need them. Better to build it resilient and you wont have any issues.

[NeilChapman]

Less than 50 ms response time is what I've seen.