View Single Post
  #20  
Old September 4th 03, 08:10 PM
Dan Foster
external usenet poster
 
Posts: n/a
Default

In article , Boll Weevil wrote:

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.


Rough calculations shows that using hardware compression for a LTO-2 setup,
one could do all of the above in about 2 (or so) fully decked out IBM 3584
LTO libraries (just as an example), assuming an average size of directly
attached storage for each of the NT servers being 1 TB. A decked-out LTO-2
library with 6 frames should yield in the neighborhood of about 720 TB of
tape storage capabilities.

If 1200 servers * 1 TB = 1200 TB; that'd be one decked out LTO library and
a second library with about 240 TB of available tape space. For the other
stuff... 13 * 7 = 91 plus 45 TB = 136 TB. So you'd still have 104 TB of
free data space, and capable of doing a single full backup for everything
with two libraries and about 3500 tapes.

This assumes 400 GB (hw compressed) LTO-2 tapes; if you are using 20 GB
tapes in uncompressed mode, then your tape requirements goes up by 20 times
3500 for at least 70,000 tapes. Also, if the average per-NT server for
storage is other than 1 TB, that would also influence number of tapes
required, as well.

-Dan