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A SAN of a WAN problem.

By boriqua1 ·
Recently, my company doubled in size by employees and datacenters through an acquisition of another company. My boss has presented the idea of using the newly acquired site for our disaster recovery site and replicate our SAN storage data to them. I currently run full backups every night that total in approximately 1.2 Terrabytes of data. He (my boss) decided that a DS3 line would suffice for the replication of the 1.2 Terrabytes, but I calculate this would take about three weeks. Obviously this would not work and installing OC-48 circuits is out of the question. Does anyone know of whitepapers or case studies of companies trying to replicate disk-to-disk backups of this size over a WAN connection? My goal is to present the infrastructure and technologies needed to accomplish this feat.

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Several ideas

by Cactus Pete In reply to A SAN of a WAN problem.

You might want to look at "seeding" copy the data to additional hardware, and send the hardware over. Then when you're making additions to the backups [not always fully resynching, I hope] that much traffic will fit over your pipes.

If you are doing full backups each night, you might consider changing strategies. Rather than spending the money on a fatter pipe, perhaps you want something like eVault to run your backups. We now backup each site locally, then backup the backups to the remote sites.

The % change for the backups is relatively small and easily fits over one to four T-1s. (several remote offices of various sizes)

I'm not associated with eVault, but we somewhat recently moved to their technologies (away from Veritas) and the whole team is rather enthusiastic about how much faster and easier the backups have become. When I find software like that, I share it.

From a support viewpoint, they have also been great. I highly recommend looking into them (or someone ith technology like theirs) before throwing money at a bigger pipe.

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I see what you mean.

by boriqua1 In reply to Several ideas

Sync'ng the hardware locally then shipping it to the remote location is actually the smarter idea. Changes (or differentials) can be done overnight across the WAN. If there were a mass disaster then we can always restore from tape, but anything else can be done from SAN to SAN. Full disk-to-disk backups would still be a viable solution, just resync only what has changed and should be okay.

Thanks so much for your input, Dpetrak!

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sync or async replication

by hgreen In reply to A SAN of a WAN problem.

YOu might want to investigate synchronous or asynchronous SAN replication. This approach provides a realtime (sync) or deferred (asnyc) replication capability. Also the use of a "snapshot" of the data and then performing backups from the "snapshot" might solve the issue.

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One other thing

by boriqua1 In reply to sync or async replication

Our most important data (SQL) is recreated every night! My company's data is ITD (inception-to-date) which is in a nut shell every thing from day one until today. This means that I cannot perform differentials on most databases, with the exception of documents in the file server. Some of the database are not that large, but collectively we could be talking in the range of 100Gb to 200Gb of databases. We may end up needing a very high bandwidth circuit to accomodate our DR strategy.

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TLog backup, transfer and restore

by mgluscevic In reply to One other thing

Is it possible to make several transaction log backups for SQL, for example every 30 min., copy them across WAN and restore on DR site ?


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sql server

by owen.payne In reply to TLog backup, transfer and ...

yep, you cna do the tlog backup overnight, enterprise edition of sql 2000 is easier to do this on, put the database into full model and get the database to backup the tlog every hour and transfer this across and apply this log to a copy of the server you have created the other end. sql 2005 makes this a lot easier as it is designed with this functionality in mind and it isn't too far away now.

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by muratanur In reply to sync or async replication

We do use Rsync todo incremental backups with the
security of SCP command. Also we do backup only
data and information and when things go wrong we
do not bother to restore the data we simply mount
the this directories over the wan as samba/nfs
directories. We do backup multiple servers this
way and it doesn't let us down

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More on async copy

by icarlock In reply to sync or async replication

I do not know which is your storage hw, what kind of arrays you have (if any). If you have arrays enabled with iSCSI and you can use them to do replication via ip altogether with suitable software. I can tell at least of one: EMC's Incremental Sancopy. Using that you dont have to do full copies all night, it will just copy the data that has changed the night before, so I think that could help with the bw problem.


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by ogroup In reply to A SAN of a WAN problem.

Evault has a good product and it works very well, if you are interested let me know, and we can discuss or talk over the phone. Email me your personal or company contact infomration.


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NetApp storage eliminates these concerns

by leishirsute In reply to A SAN of a WAN problem.

NetApp storage works in a SAN and NAS environment simultaneously and its disk to disk backup is at the block level. So, its use of WAN backup is optimized. The federal government loves using this technology for local central repositories that store repllicated backups from remote locations.

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