network + sql backup file copy to another server

Trying to understand this from a n/w perspective.
We have multiple backup files that we try and copy(copy,xcopy or robocopy)
to a secondary server thats Gig attached on the same LAN. When we issue one
DOS Session to start copying an individual file, why doesnt it use the
entire throughput of the NIC ...as an example, the bytes sent/sec might be
say 2000000, when we invoke another session and start copying another file,
the bytes sent/sec now jumps to say around 3500000. So my question is why
with one DOS Session, it does not push at 3500000 . Is there a DOS
Limitation ? Trying to understand the n/w concepts here. The numbers I have
listed are not accurate but always noticed a major increase when multiple
sessions are opened for the file copying..
I know this is not a SQL Server related question but any help here would be
appreciated from the experts hereHassan,
There may be other limiting factors than the network bandwith. For instance
you have the Disk I/O, the controller's channel and bus bandwidth, cpu etc.
If the file being read from a single thread or in parallel? I would check
perfmon to ensure you don't have other bottlenecks affecting the tests.
--
Andrew J. Kelly
SQL Server MVP
"Hassan" <fatima_ja@.hotmail.com> wrote in message
news:OzV9xuKhDHA.1008@.TK2MSFTNGP12.phx.gbl...
> Trying to understand this from a n/w perspective.
> We have multiple backup files that we try and copy(copy,xcopy or robocopy)
> to a secondary server thats Gig attached on the same LAN. When we issue
one
> DOS Session to start copying an individual file, why doesnt it use the
> entire throughput of the NIC ...as an example, the bytes sent/sec might be
> say 2000000, when we invoke another session and start copying another
file,
> the bytes sent/sec now jumps to say around 3500000. So my question is why
> with one DOS Session, it does not push at 3500000 . Is there a DOS
> Limitation ? Trying to understand the n/w concepts here. The numbers I
have
> listed are not accurate but always noticed a major increase when multiple
> sessions are opened for the file copying..
> I know this is not a SQL Server related question but any help here would
be
> appreciated from the experts here
>|||With one DOS session, it looks like it can peak at a certain rate and then
when i open more and start copying other files, it increases and if i
cancel/close some sessions, i can see it decrease and was wondering why one
session cant take it all at first and if I open more DOS sessions, the rate
should remain the same ...
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:uAfiPvPhDHA.1340@.tk2msftngp13.phx.gbl...
> Hassan,
> There may be other limiting factors than the network bandwith. For
instance
> you have the Disk I/O, the controller's channel and bus bandwidth, cpu
etc.
> If the file being read from a single thread or in parallel? I would check
> perfmon to ensure you don't have other bottlenecks affecting the tests.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "Hassan" <fatima_ja@.hotmail.com> wrote in message
> news:OzV9xuKhDHA.1008@.TK2MSFTNGP12.phx.gbl...
> > Trying to understand this from a n/w perspective.
> > We have multiple backup files that we try and copy(copy,xcopy or
robocopy)
> > to a secondary server thats Gig attached on the same LAN. When we issue
> one
> > DOS Session to start copying an individual file, why doesnt it use the
> > entire throughput of the NIC ...as an example, the bytes sent/sec might
be
> > say 2000000, when we invoke another session and start copying another
> file,
> > the bytes sent/sec now jumps to say around 3500000. So my question is
why
> > with one DOS Session, it does not push at 3500000 . Is there a DOS
> > Limitation ? Trying to understand the n/w concepts here. The numbers I
> have
> > listed are not accurate but always noticed a major increase when
multiple
> > sessions are opened for the file copying..
> >
> > I know this is not a SQL Server related question but any help here would
> be
> > appreciated from the experts here
> >
> >
>|||I see now. Not sure why that is unless each DOS session is just single
threaded and can't read as fast as the network can handle.
--
Andrew J. Kelly
SQL Server MVP
"Hassan" <fatima_ja@.hotmail.com> wrote in message
news:%23wqnmaRhDHA.3272@.tk2msftngp13.phx.gbl...
> With one DOS session, it looks like it can peak at a certain rate and then
> when i open more and start copying other files, it increases and if i
> cancel/close some sessions, i can see it decrease and was wondering why
one
> session cant take it all at first and if I open more DOS sessions, the
rate
> should remain the same ...
>
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:uAfiPvPhDHA.1340@.tk2msftngp13.phx.gbl...
> > Hassan,
> >
> > There may be other limiting factors than the network bandwith. For
> instance
> > you have the Disk I/O, the controller's channel and bus bandwidth, cpu
> etc.
> > If the file being read from a single thread or in parallel? I would
check
> > perfmon to ensure you don't have other bottlenecks affecting the tests.
> >
> > --
> >
> > Andrew J. Kelly
> > SQL Server MVP
> >
> >
> > "Hassan" <fatima_ja@.hotmail.com> wrote in message
> > news:OzV9xuKhDHA.1008@.TK2MSFTNGP12.phx.gbl...
> > > Trying to understand this from a n/w perspective.
> > > We have multiple backup files that we try and copy(copy,xcopy or
> robocopy)
> > > to a secondary server thats Gig attached on the same LAN. When we
issue
> > one
> > > DOS Session to start copying an individual file, why doesnt it use the
> > > entire throughput of the NIC ...as an example, the bytes sent/sec
might
> be
> > > say 2000000, when we invoke another session and start copying another
> > file,
> > > the bytes sent/sec now jumps to say around 3500000. So my question is
> why
> > > with one DOS Session, it does not push at 3500000 . Is there a DOS
> > > Limitation ? Trying to understand the n/w concepts here. The numbers I
> > have
> > > listed are not accurate but always noticed a major increase when
> multiple
> > > sessions are opened for the file copying..
> > >
> > > I know this is not a SQL Server related question but any help here
would
> > be
> > > appreciated from the experts here
> > >
> > >
> >
> >
>