>E Gold wrote:
>> Hi all
>> 
>>  << Original Email removed >>

>   Let's do some math:

>   You do 800Gb/10h = 22Mb/s.
>   GigE is 1000/8=125Mb/s.
>   LTO-2 is 30Mb/s (native).

>   For your current Lotus needs (and some growth) a single GigE link is 
>enough.

> You didn't describe how many sessions the Lotus server (or its backup 
>agent) can do at the same time. I would also suggest that you will try 
>to monitor the performance on the Lotus server and see if you can see 
>any CPU or disk I/O bottlenecks on it.

        You have an assumption in your math section that is not valid.  You 
assume that GigE can perform at 125M/sec.  And theoretically, that's correct.  
The same way, theoretically, a 100Mb NIC can do 12.5M/sec.  However, the 
reality is that the overhead on a 100Mb means 8-9M/sec is realistic throughput 
for client data.  
        And while you'd think that'd mean that a realistic throughput for GigE 
then must be 80-90M/sec (GigE=10*100Mb), the fact is that 40-50M/sec is all you 
can expect to see out of a GigE card, out of the box, without some level of 
performance tuning.  With extensive tuning, I've seen people get up to 70M/sec 
out of a GigE...maybe the occasional burst higher.  But in the cases I've dealt 
with directly, we've come to the conclusion that an out-of-box GigE is the 
equivilent of 5*100Mb, or half what the specs lead you to believe.
--Ted

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