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The 44 hours would be for the first "full" backup - after that most of the online backups only backup what has changed.  You could start the full over the weekend and then it would only backup what has changed.  I currently use the professional version of ibackup.com for an engineering business (think big cad files) and it works very well for 100GB using a T1.  It keeps the last 30 versions of any file and is always done by morning.
 
Jeff
 
Jeff Wallis
Chief Network Engineer
Chittenden East Supervisory Union
802-858-1727 voice
802-899-4281 fax
http://help.cesu.k12.vt.us
 
 

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>>> David Storandt <[log in to unmask]> 11/2/2009 10:14 AM >>>
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>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Currently we back up about =BD+ TB to disk and then that goes to tape, as =
it
takes too long to go straight to tape.   Dropbox at $240/year for 100GB
would cover a fair amount of data, but would that solve more problems than
it would create?  Amazon can host all of our backups for about the cost of
our tapes for 1 month=85 but can we even begin to push that amount of data =
up
to the cloud with a tiny 30MB handoff?  How big a pipe do we need to
realistically use these solutions and will that cost be worth it?

Say 600GB of data:

600GB =3D 600,000 MB * (8 bits/byte) =3D 4.8x10^6 Mbits / 30Mbps =3D 160,00=
0
seconds =3D 44.5 hours.

If 5 hours was a requirement (common for direct-to-tape), you'd need 270Mbp=
s
dedicated to your backups, plus line overheads and other usage. Call it a
300Mbps connection, but only for your 5 hour window.

If 24 hours was an option (local disk buffers and Sunday pipe usage), 60Mbp=
s
could work.

Any connection will have TCP (4%) or crypto 3DES/AES (15%) overheads on the
connection, plus any control traffic for your data streams. If you are usin=
g
your connection for other stuff at the same time (regular Internet usage,
VPNs, remote classrooms, etc.) or the file host won't accept at that high
data rates, your connection will need more time to finish the job.

-D

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<span style=3D"font-size: 11pt; color: rgb(31, 73, 125);"><br>&gt;&gt;&gt;&=
gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;=
&gt;&gt;&gt;&gt;&gt;&gt;&gt;<br>=A0Currently we back up about =BD+ TB to di=
sk and
then that goes to tape, as it takes too long to go straight to tape.=A0 =A0=
Dropbox at
$240/year for 100GB would cover a fair amount of data, but would that solve
more problems than it would create?=A0 Amazon can host all of our backups f=
or
about the cost of our tapes for 1 month=85 but can we even begin to push
that amount of data up to the cloud with a tiny 30MB handoff?=A0 How big a =
pipe
do we need to realistically use these solutions and will that cost be worth=
it?</span><br><br>Say 600GB of data:<br><br>600GB =3D 600,000 MB * (8 bits=
/byte) =3D 4.8x10^6 Mbits / 30Mbps =3D 160,000 seconds =3D 44.5 hours.<br><=
br>
If 5 hours was a requirement (common for direct-to-tape), you&#39;d need 27=
0Mbps dedicated to your backups, plus line overheads and other usage. Call =
it a 300Mbps connection, but only for your 5 hour window.<br><br>If 24 hour=
s was an option (local disk buffers and Sunday pipe usage), 60Mbps could wo=
rk. <br>
<br>Any connection will have TCP (4%) or crypto 3DES/AES (15%) overheads on=
the connection, plus any control traffic for your data streams. If you are=
using your connection for other stuff at the same time (regular Internet u=
sage, VPNs, remote classrooms, etc.) or the file host won&#39;t accept at t=
hat high data rates, your connection will need more time to finish the job.=
<br>
<br>-D<br>

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