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Old September 4th 03, 04:40 PM
Boll Weevil
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On 3 Sep 2003 14:55:07 -0500, Eric Lee Green wrote:

In article , Boll Weevil ruminated:
First of all, nobody makes a robotic hard drive changer. We go through
about 500 tapes a day using 20 to 40 tape drives concurrently all
managed by automated robotic tape libraries. I can't imagine to trying


Let me get this straight. You back up 50 terabytes per day? Or are you
using older/smaller capacity technology, let's say DLT1, and backing up,
say, 10 terabytes per day?

10 terabytes per day = 3650 terabytes per year. You're saying that your
installation is pushing 3650 terabytes of data per year through your
systems? Or are you saying that, due to the inefficiencies of current
tape backup solutions (which operate upon a whole-file basis rather
than on a differential block basis), you need 3650 terabytes of tape storage
to store, say, 365 terabytes of changed data?



See if you can add this up. To start, we have about 200 Sun servers and
about 1200 NT servers. About 100 Sun servers and about 100 NT servers
are on the SAN and share the following EMC and Hitachi subsystems:

7 EMC 8830 frames with about 13 TB raid 10 useable, each
1 Hitachi 9980V frame with about 45 TB raid 5 useable

There are a whole lot of direct attached SCSI disk arrays and internal
disks in each of the 1200 NT servers. I can't even start as to how much
storage these servers account for. These all get backed up.

We use STK 9840A and 9840B drives. These drives can do about 20GB per
tape at about 20 to 40 mb per second.

500 tapes??? Well, I think I've mistaken or I kicked out an old number.
We probably use twice that. Most of the SAN disk is used for Oracle and
SAS databases. Oh yea, we also have about 200 TB of mainframe but IBM
manages that. So, do some math and figure out how many tapes we use on
a full backup. You can save me some time.