That is true. It also depends on where the command is initiated. Using the NFS method, tar is executed on the local system (eg. the server with the tape drive), and will be using the CPU and memory on that system. The remote system is involved only in file service. Running tar on the remote machine will, as you point out, use the CPU on the remote machine, and allow for the compression of data before sending the data across the network. But, using SSH, you then have an encryption/decryption overhead. If network overhead is an issue, you can mitigate that by using rsh. If both systems are behind a firewall, you can safely leave and rshd and rexecd port open in inetd.conf and use rsh rather than ssh. So the issue comes down to: 1. Network overhead (compression vs. no compression) 2. command complexity. If you want to initiate the transfer from the local machine (eg. machine with the tape drive). NFS makes the command simpler at the expense of not compresing the files over the network. Otherwise, you would need to case the command to be initiated on the remote machine. In a small network, you can have the remote machine initiate the command if you know the tape drive is available or you do it by hand. 3. security. You may want to add the security of ssh even behind your firewall. Depends on who uses the systems. In a home environment where access to the computers is limited you don't need ssh within your firewall, but even in a small commercial environment, you might want to use ssh. (As an aside, in many environments, your greatest exposure may be what is behind the firewall, not who is outside trying to get in).
On 25 Feb 2002 at 13:34, Paul Lussier wrote: > > In a message dated: Mon, 25 Feb 2002 13:29:31 EST > "Jerry Feldman" said: > > >Remember that ssh will add a significant overhead. > > More or less than the overhead of NFS? The nice thing with tar is > that if you have a pretty hefty CPU in the local system, you can run > it though gzip and compress it *before* sending the data across the > network. With NFS, you don't really have that option. > -- > > Seeya, > Paul > > -- Jerry Feldman Portfolio Partner Engineering 508-467-4315 http://www.testdrive.compaq.com/linux/ Compaq Computer Corp. 200 Forest Street MRO1-3/F1 Marlboro, Ma. 01752 ***************************************************************** To unsubscribe from this list, send mail to [EMAIL PROTECTED] with the text 'unsubscribe gnhlug' in the message body. *****************************************************************
