HA over subnets

[robnoble]

Can somebody please assist, I'm looking to put vSphere in and we are wondering if you can have any fault tolerance over subnets ? I want a cluster on each physical site but if possible would like failover across the sites ?? is this possible

Thanks.

[depping]

Are we talking FT(Fault Tolerance) or HA(High Availability)? You want to create stretched clusters, can you give us an idea of the bandwidth between the sites / latency etc. Keep in mind for HA/FT to work you will need to be able to access the shared storage from both sites at the same time. In other words I/O will need to cross the line before it's written.

I must say that stretched clusters is usually not a best practice.

Duncan

VMware Communities User Moderator | VCP | VCDX

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[AndreTheGiant]

I want a cluster on each physical site but if possible would like failover across the sites ??

You can do with VMware Site Recovery Manager.

But you need a storage base replication.

Or you will have the SAME storage on the two sites?

Andre

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[robnoble]

thanks for the response.

We will have a 1gig link between the sites, I just would like an idea of the best way to approach failover off site ? Cost is no issue.

[AntonVZhbankov]

1) Do you want HA or FT?

2) Can you provide storage synchronization between sites on SAN-level?

3) What is latency and bandwidth between sites?
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[AntonVZhbankov]

What level of high availability do you want?

Is a couple of hours acceptable, a couple of minutes, or do you really need zero downtime?

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[robnoble]

I think its HA i want, i have been told that in order to have HA i will need some SAN replication software would this be correct ?

[robnoble]

I want zero downtime if possible.

[AndreTheGiant]

i have been told that in order to have HA i will need some SAN replication software would this be correct ?

It depends.

If you want a complete HA also in case of site disaster, you need a second storage, a replication between storage, and maybe VMware SRM.

Andre

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[AndreTheGiant]

I want zero downtime if possible.

In this case you need something more.

Maybe some storage virtualization solutions (for example the one from DataCore).

And VMware FT or cluster inside VMs.

Andre

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[robnoble]

Well in my design i have -

2 servers on each site with a disk shelf attached on each site using fibre,

[AndreTheGiant]

2 servers on each site with a disk shelf attached on each site using fibre,

What do you mean with "disk shelf attached on each site using fibre"?

Andre

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[depping]

I suggest you read the following topic first: http://communities.vmware.com/thread/193368?tstart=0

Identify what your needs are before everyone starts suggesting Features and possibilities which might not even make sense.

SRM = Site Recovery Manager -> Disaster Recovery Scenario's. Downtime during failover - you will need array replication

HA = High Availability -> Downtime during failover - you don't need array replication but hosts must be able to read / write from the same array (So preferably within 1 site, or you will need a very good low latency connection)

FT = Fault Tolerance -> No downtime during failover - you don't need array replication but hosts must be able to read / write

from the same array (So preferably within 1 site, or you will need a

very good low latency connection)

Duncan

VMware Communities User Moderator | VCP | VCDX

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[robnoble]

The storage will be attached to the servers using iscsi or fibre,

[robnoble]

Thanks for the summary, I do believe FT would work in my companies case. Can you point me in the right direction for resources for this please.

Thanks.

[AndreTheGiant]

If all the host are on the same storage, then VMware FT can be the solution (but if possible use more that 1 Gb/s link to connect the two sites).

Andre

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[AntonVZhbankov]

FT VMs have several restrictions. For. ex. FT VM can have only 1 CPU.

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