Storage Area Networks For Dummies®

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remote offices. But what about large insurance companies and financial institutions
that have really large amounts of data gathered every day at the local
office? With hundreds of brokers located around the country gathering client
data on their laptops, perhaps with a server or two located in the office that
provides access to corporate e-mail, how do you back up all that stuff?
One solution that works is to use the server in the office as a file server, to
which all laptop users connect when it’s time to store their data. The server
is then connected via the corporate IP network, using both a network card
and an iSCSI card. The network card connects clients to the server; the
server uses the iSCSI card to connect to a tape library located at the central
office. The tape library is connected to an iSCSI bridge, which is also connected
to the corporate LAN through the iSCSI bridge. Each server at every
remote office sees the tape library as if it were connected locally. No Fibre
Channel SAN is needed for this connection.
For this solution to be effective, you need backup software that allows sharing
of tape resources. Most backup software vendors have this capability.
You’ll also have to do an initial full backup, which could take a while over
the slow links on a wide area network (WAN). After the full backup of each
remote office is complete, then you need run only differential backups.
Because a differential backup backs up only the changes since the last differential
backup, only a small amount of data needs to be pushed over the WAN
for each remote server.
You Need to Replicate Your Data for
Disaster Recovery but Can’t Afford Fast
WAN Connections
This is a common problem. The most expensive part of data-replication solutions
is the money you have to pay to lease network connections between
your buildings. For those of us without deep pockets, this can be an issue.
One way to accomplish remote copy of data is to use the CTAM (Chevy Truck
Access Method). That’s right, Chevy truck, although you could use a Pontiac
sedan or even a van to accomplish the same task. Here’s the deal: You back
up your servers to tape, throw the tapes in the back of a vehicle, and transport
them to your remote site. In the event of a disaster, you restore the
tapes to the new servers that you just bought and get back to work. It might
take a week or two for you to get back to business as usual if you use this
method, but hey, you get what you pay for.