Step 4: Backups? Who needs backups?

Scaling WebObjects
Example Apps
Step 0
Step 1
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Step 5
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Summary
Postscript

For WebObjects since there's nothing stored on that server, we can backup the server to a tape drive, that's not a big deal. Same with the image server. So we can buy one G3 machine to serve as a backup for both machines. We'll make sure that the images from the image server are mirrored on the new system, along with the WO application. If the image server goes down, we just adjust the DNS entry to point temporarily at the new G3 machine. So for $3K (an extra $1K worth of memory) we can backup the WO and image servers.

The database server is more tricky. What we need to do here is setup two machines to mirror each other, and run the database on both of them. If you buy Oracle 8E, you can set it up so that two machines look like one database, and they back each other up.

So that's $50K for Oracle 8E, times two machines is $100K. We'll need another midrange Sun box, that's another $35K. Another week of engineering to set it up and we've just added $6K. We can get the original $15K for Oracle 8 back since we're upgrading, so that helps. We've just spent $126,000.

At this point, we've got more database capacity then we need for 100 pages per minute, so WO is probably the limit. But wait, we've got a G3 that can run WO just fine working as the backup machine. Since we have a 100 tpm license on the one G3 from the last scale step, and a 50 tpm license on the "backup" G3, if we distribute the initial connections by users between these two machines it a 2-1 ratio, we can get effectively an 150 tpm license. (see Postscript for a note on this.)

Which is more then our T1 can handle. Time to upgrade our network connection!

Next Page: Scaling step #5: At long last the unlimited WO license...NOT!

Nile.com bottom line:

Initial Engineering $72,000

HW investment: $204,700

Network: $1000/month.

Max ppm: 120 (limited by T1 line)

Max profit: $576,000/month

Yippee.com bottom line:

Initial Engineering $24,000

HW investment: $204,700

Network: $1000/month.

Max ppm: 150 (limited by WO license)

Pages/day: 72,000

Max users: 2,880

Cost per user/month: $8.29