network speeds over time..

I was wondering if anyone could shed some light on a network speed issue. we
have a database to backup that's 766GB. at first the backup starts off
pretty well at 30MB/s but over time it just keeps getting slower and
slower... towards the end it ended up under 10MB/s

I have tried different methods of copying the file and it doesn't seem to
matter the performance degrades over time regardless.

its obviously hard to give info on this, but I was wondering if this was a
known issue and if there was any way around it. typically restarting the
copy helps with the speed, but that really isn't the best option.

what would cause the speed to drop?

Thanks
Justin

 

Which methods you tried ?
Robocopy ?
eseutil ?

 

I tried a straight copy (pretty slow) I tried robocopy (was ok, but wasn't
the highest speeds) and I used Repliweb and netbackup, both of which started
off at about 30MB/s which only held for roughly 2 hours and after that I saw
a steady continuous drop in speed.


Justin

 

Can you try with eseutil ? it is meant to copy very large file

 

Thats a good idea, i actually forgot about that.. from my understanding most
programs use a windows copy function where as the eseutil actually uses a
read/write method which makes it quicker with less overhead.

i'll give that a try but mostly i'd like to figure out why a large(long)
transfer like this would start to slow down over time.

Justin

 

If it doesn't do the job:
Check for antivirus (to exclude source & destination on both side)
check for scheduled task that may makes a lot of I/O (defrag, full antivirus
scan)
You may use a sniffer like Wireshark or Microsoft Network Monitor 3.1 to
check against packets. As Laura Chappell said during techED, "Packets never
lie !"

 

awesome, looking in to that now. we have 2.6 but we can probably get it
upgraded.

thanks for the info

Justin

 

there are no scheduled tasks, its just a steady drop. the link rakefet sent
in regards to repliweb gives a pretty good pictorial of whats going on with
their example of the FTP transfer which i guess they are saying is packet
loss and TCP errors.

i have used wireshark but im still kind of new too it. is there any links
for web resources on this topic in particular or could you give me a brief
run down of what i would be looking at/for?

Thanks
Justin

 

ps: im using eseutil right now and its off to a strong start using 50% of a
gig connection. I have started some perfmon logs to keep an eye on this to
see how it degrades over time.

Justin

 

Looks great, keep us informed !

 

with eseutil it took about 4 and a half hours to transfer 830GB... worked
out pretty well and held strong the whole time.
Going to try the RDS since we own it and see how that works out, but im
pretty happy with how eseutil handled it.

Thanks for the help.

Justin

 

great