I can't see anything wrong in the calculations except that you can't expect 
to get 100Mbit/s data over a normal 100Mbit/s network.

The most simple way to solve part of your problem is to buy a Gbit switch 
and some Gbit NIC's.

You could also attach the tape drives directly to the server and install a 
media server on it (but that cost more then buying a small Gbit/s switch)

/johnny

At 16:23 16-08-2003 -0400, Cecil Hypolite wrote:
>Hi all, I have a little backup dilemma and I wish to get some help on
>
>I have to do a weekly full backup of a system that has 17 partitions and
>about 500 GB of data. The backup will be done on the weekend, when there are
>few other jobs running. Here are some specs:
>network: 100 MB/sec (12.5 MB/sec)
>SCSI-2 connection : (40 MB/sec)80 MB/sec (two drives)
>Drives: 2 SDLT220's 79.2 GB/hr
>Produce: Netbackup Datacenter 4.5
>
>It seems that the network is a bottle neck as it can only transfer 45 Gb/hr
>(3600 *(12.5 MB/sec) = 45 GB/hr)
>With that network transfer speed of 45 GB/hr I should be able to back this
>500 GB of data within a 12 hour window (11.2 hours to be exact), are my
>calculations correct?
>
>-Also since the network transfer speed is only 45 Gb/hr I should not
>implement multiplexing, as one of the drives will start "shoe shining"
>because the network cannot sustain a transfer rate of 79.2 GB.hr. Is this
>correct?
>
>Any suggestions will be greatly appreciated.
>Thank you,
>Cecil Hypolite
>
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