WAN Replication - iSCSI

[mark_odell]

Hi

I am looking to set up a system to replicate data between site A and site B and would like you advice on how to proceed and if this will work.

The only part of the system in place right now is the connectivity. Site A has a 100mbps line and site B has 10mbps. They have a VPN, which get somewhere between 5mbps and 10mbps.

The data at the source (site A) is a backup of other servers in our system, so it's not that important if the destination is always fully up to date as long as the system actually works and the data is always accessible at the destination. e.g. in the unlikely event that we lose site A completely, we need to be able to get back the data from site B, sometime within the last few hours.

This will start off at 2TB, but if possible I want a system to allow 15TB between two units. I would expect it to change under 10GB per day.

So my questions are:

1 - Will your replication system work in this situation?
2 - What will happen if we lose connectivity?
3 - If during a busy time it falls behind, will that leave site B unusable, or just a bit behind, but still OK?
4 - What spec of server do you recommend to run this

Thanks in advance
Mark

[mark_odell]

Nobody out there tried this?

I have now ordered my servers with Open-E so will have to try it out, but would be nice if Tom could say if it will in thoery work?

[To-M]

1 - Will your replication system work in this situation?
Absolutely, the bottle neck will be the the VPN speed, which will not be a problem in your case.

2 - What will happen if we lose connectivity?
If the connection is lost then replication will begin again, and it only synch the data that was not transferred. This will happen because of the ECC check of the transmitted data. And as long as the replication is active and there are no error-messages, the copy is consistent.

This can easily be tested by downloading our Demo-CD from our website to replicate this issue to see how the data is consistent.

3 - If during a busy time it falls behind, will that leave site B unusable, or just a bit behind, but still OK?
It will still be OK, only the data that has not been transferred during the fail. Once connection is re-established then the synchronization of the data from the source will continue to destination as it should be. If site A fails, then you need to promote site B to become your source.

4 - What spec of server do you recommend to run this...
For what you have I would recommend a high speed dual core CPU (high cache count) and 4GB of RAM and a good controller that has the write back enabled. We tune our product on the Intel server from link below or follow the same specs.

http://www.open-e.com/data_storage_s...bserv=prodcomp

Write now the synch limitation is 4TB per volume, so it should be good enough for you. And if you have more than 4TB, you can create multiple volumes that each of them replicate 4TB. Please keep in mind that in the future releases we will fix this to replicate 16TB per volume.