File-Based Methods


These transport methods include e-mail, ftp, and physical media (like CDs, magnetic tapes, and diskettes).

Using Electronic Mail

You can use an existing electronic mail mechanism as the transport method for packets. On the sending end, compress and encode the packet; then send the resulting data to a specific mail alias at the receiving site. On the receiving end, redirect the mail alias to a script that decodes and decompresses the incoming information. To ensure that a mail message is not too large to be delivered, you can specify the maximum size for a packet by using the –maxsize option, the shipping.conf file (UNIX), or the MultiSite Control Panel (Windows).

Advantages:

Disadvantages:

Notes:

Using FTP

The ftp utility can transport packets between replicas. On the sending end, the MultiSite administrator or a script creates and compresses the packet, and uses ftp to transfer the file to a location that is accessible by MultiSite administrators at other sites. Scripts at receiving sites poll the drop site, looking for any new files. When new files arrive, the scripts retrieve them using ftp, decompress them, and process them.

Advantages:

Disadvantages:

Using Physical Media

You can create packets as files, write them to a CD, magnetic tape, or diskette, and then send the media to another site. The mkreplica and syncreplica commands include the –out option, which places packets in physical files.

When you use the –tape option (UNIX) or a file-based method for transport, you may need to use the –maxsize option to prevent the tape from filling up or to ensure that the file is a manageable size. In this example, the administrator writes the replica-creation packet to tape, using the –maxsize option. The mkreplica command prompts for additional tapes if necessary.

MINUTEMAN% multitool mkreplica –export –work /usr/tmp/wk  –tape /dev/tape 
–maxsize 75m goldengate:sanfran_hub@/vobs/dev 
Enabling replication in VOB.
Comments for "sanfran_hub":
First time replication for dev VOB; Creating new replica, sanfran_hub, on host 
goldengate 
. 

Please insert a tape to hold packet number 1.
When ready, enter ‘proceed’ (proceed/abort) [proceed] <RETURN> 
Generating packet number 1...
Dumping database...
  . . .
Dumper done.