For small businesses on a budget, backing up network systems can be
expensive, time-consuming, and difficult. I developed a solution that makes
network backup more economical by using built-in tools on Windows NT 3.51 and
4.0 systems. My solution consists of a simple backup script (batch file) that
contains commands for running the NT backup utility--NTBACKUP. You use the NT
Command Scheduler or AT command to schedule when the script will run. These
tools let you perform unattended scheduled backups of any network drive you can
connect to, including shared drives on Windows 95 and Windows 3.11 machines and
NT systems.
Getting Ready
To use this backup method, you need Administrator privileges. Also, you must
install a tape backup device on the NT machine on which you'll run the backup
script.
Before writing the script, make sure you can connect to (i.e., mount)
shared drives on the machines you want to back up. In a workgroup environment
that has a separate user database for every system, you must have an account
with sufficient privileges on each machine. I recommend creating an account for
the sole purpose of backing up the system. Give this user a name such as Backer,
and assign it the User and Backup Operator groups only. If you use domains,
create a user on the Primary Domain Controller (PDC) with the group settings
mentioned above; use this account to connect to all shared drives.
An easy way wto test whether a user has sufficient privileges is to try to
connect to the shared drive under File Manager, while substituting the new user
in the Connect As box in the Connect Network Drive menu option. If you receive
the Network path was not found error, the share is unreachable, and you
need to verify that the share is present. If you receive the Access denied
error, you probably don't have sufficient privileges; correct this at the share
by including access to all users (if security is not a concern) or only to the
user you created to conduct the backup operations.
Before you write the script, you also must decide where to save the log
files. I recommend an easy-to-remember yet secure location on the server that is
doing the backup. I place the log files in a directory called LogFiles, in a
subdirectory of the NT system directory. If you choose to store the log files on
a network drive, make sure your connection will be stable for the duration of
the backup.
At this point, you might find it convenient to organize a list of the names
of the machines you want to back up, the shared drive names on those systems,
and passwords required to connect to those systems or drives. Before you start
the backup, test whether you can connect to the shared drives and have authority
to back up all appropriate files.
Creating a Backup Script
Listing 1 shows the commands for a sample backup script (BACKUP.BAT). The
script follows a basic format. First, you connect to a shared drive on a remote
NT machine and assign it a drive letter. Next, you use the NTBACKUP command to
copy the drive's contents to tape. When NTBACKUP has finished copying the drive,
you delete the mount (i.e., disconnect the share) and start again on another
shared drive. In this way, you back up all shared drives sequentially. NT adds
each shared drive's contents (i.e., backup set) in turn to the backup tape, and
each backup set has a section in the backup log.
Exploring the Backup Script
You can write the script using any text editor. Use the sample as a template
for your script, although you will need to change some arguments for your
system's specific configuration. Words in angle brackets are sample text; you
must change them to fit your network environment. For example, in the first
line,
net send <user> Backup Started
you must change the word user to an actual user who will receive the
message Backup Started when NT runs the script. The sample script
includes net send messages at the beginning and the end to let the user
know that the script started and ended successfully. The messages also include,
by default, the times the system sent the messages. Because these times
correspond to the start and end times of your script, you can easily calculate
how long the entire script took to run.
The statement in callout A in Listing 1 tells the system to perform several
tasks: Back up the local C drive, include a comment (/d), include the local
Registry in the backup (/b), use hardware compression (/hc:on), perform a
particular backup type (/t), write the results to a log file called backup.log
(/l), and designate which tape drive you want to use (/tape). Note that the /t
switch can be followed by normal, copy, incremental,
differential, or daily, depending on the type of backup you want
to do. You set another switch, /tape, to 0, if you're using the first tape drive
installed. A value of 1 means the second tape drive, 2 the third, and so forth.
Notice also that I include a full path to the log file, starting with the
environmental variable %windir%. This variable lets you use the script
on other machines with little modification.
The lines in callout B in Listing 1 tell the system to back up a network
shared drive on an NT system. First, you connect to the share and assign it a
local drive letter (in this case, X). This line uses the authority of user
Backer in domain domainname to connect a share on a workstation. You must
include this user's password in the script. Because the program saves this
script as ASCII text and anyone with sufficient privileges can read the script,
a security risk exists. This risk is one reason to create a user with limited
authority only for backing up shares.
Next, the script issues an NTBACKUP command to back up the X drive. This
line differs from the previous backup command (A) in two ways. First, NT appends
this backup set to the previous one (/a), so the previous backup sets aren't
erased. Second, this line has no /b switch telling the program to include the
Registry with the backup. The current version of NTBACKUP lets you back up the
Registry of the local machine only. To safely back up the Registry, including
the user database (/s), you must make a repair disk at the console for each
machine. Of course, you can use the same Emergency Repair Disk (ERD) for
identically configured systems. You will need this disk later if you have to
restore a network drive that contained a functional NT system. (For information
about ERDs, see Michael D. Reilly, "The Emergency Repair Disk,"
January 1997).
Because the number of shares you back up might change or exceed the number
of available drive letters on your system, always disconnect the share after
you've backed it up. Doing so cleanly terminates your session with this network
share and lets you reuse the drive letter. The command
net use x: /delete
disconnects the share and frees the X drive letter.
This script also includes commands (C) for backing up a Windows 3.11
machine. Use the same syntax for Win95 machines. This system need not be in your
workgroup or domain, but you must be able to resolve its Universal Naming
Convention (UNC) name (e.g., \\computername). Assuming a password
protects the shared drive, you connect to the share by executing the command in
line 11. This statement doesn't include usernames because only passwords, not
user authorization, protect Win95 and Win 3.11 shares. However, the command to
back up the share is the same as that for the NT workstation. The next line
disconnects the share. You can, of course, back up any number of different
shares, which may include other types of systems, provided you can connect to
their shares.