How much data can you move on a T-1 in 24 hrs?
This question comes up a lot in regards to data migration, and emergency data recovery. The answer is not much, but lets break down the numbers:
(1536000 bits/sec * 86400 sec in a day) / (8 * 1024 * 1024)
8 * 1024 * 1024 = 8,388,608 (8 bits in a byte, converted to megabytes)
So thats 15820.312 MB a day which becomes:
15.449524 GB a day
Thats running full bore, no packet loss, and not including headers.
A more reasonable figure would be 97.3% of that (ip and tcp headers overhead)
Figure in if the are running an ipsec vpn tunnel though even more overhead.
Multiply by 93% in that case.
Assuming little packet loss (a good circuit, good routers w/o overloaded buffers)
and low latency (40ms or less) you probably have about 90% efficiency.
So I would say a data t1 can move a MAX of 13.86 GB a day.
A safer estimate - the one you hear me more often quote is 8GB a day but thats
taking into account that during the business day the pipe will be needed for
So if you started a backup friday nite on an UNUSED, high quality t1, I would say
by Monday AM you coud move:
7PM friday to 7 AM monday =
(5 + 24 + 24 + 7) = 60 total hrs
At a pace of .5775 GB / hr:
Thats 34.65 GB over a weekend, which is not a lot but it is what it is.
Keep in mind too, that if you have a client that is bonding t1s that the
multilink ppp has some extra overhead and slight pacing issues too.
So I would estimate for a:
3Mbit bonded link: 1.1 GByte/Hour
4.5Mbit bonded link: 1.65 GByte/Hour
6.0Mbit bonded link: 2.17 GByte/Hour
So to move a 50GB vmware server image in full for example, you'd need a 4.5Mbit
link to safely pull it off in a weekend.
Even a 6Mbit 4xt1 bonded pipe would not be able to move it in a single nite.
This is probably why the metro-e 10Mbit+ and high speed comcast and fios
offerings are so critical for anyone doing any kind of serious data replication.