An access control list (ACL) is a collection of access control list entries (ACEs) that grant or deny access to an object in the system. In MEDIA, a medium or a BCKMGR job can have ACEs that limit access to them. ACLs are generally used to grant access to a system object to some users, rather than all users. When a request is made to the operating system for access to an object, the ACLs are searched for a match. If a match is found in the list, the specific access is granted.

2.2.1 MEDIA example

ACLs can be used to grant access to media to several users, creating shared media. For example, a medium called TEST_TAPE is used by both SMITH and JONES for the same purpose. The MANAGER wants to limit the medium's usage to just those two users. The command would be:

$ MEDIA MODIFY TEST/ACL=((IDENTIFIER=[SMITH],ACCESS=READ+WRITE+EXECUTE), (IDENTIFIER=[JONES],ACCESS=READ+WRITE+EXECUTE))

This would allow read, write and execute privilege to only SMITH and JONES for the medium called TEST.

2.2.2 BCKMGR example

A BCKMGR job can also have it's access limited using ACLs. Suppose a MANAGER only wants JOHNSON to be able to run a particular job. He could set the ACL using the following command:

$ BCKMGR MODIFY FULL/ACL=(IDENTIFIER=[JOHNSON],ACCESS=EXECUTE)

This example would limit execute rights on the job named FULL to JOHNSON only.

2.3 Overview of Backup/Restore

The Backup and Restore capabilities of MEDIA give you invaluable control over your off-line data management. In addition to the backup management capabilities of BCKMGR, there are three ways to restore files to suit any situation in which off-line data is need quickly and reliably. These are:

1. VAULT restore for select file restore.
2. Restore via search for MANAGER restore of groups of files through a search criteria.
3. Full disk recovery for recovery of a complete volume or volumes in the case of a disk crash or other problems.

All backup and restore features are described in the following sections.

2.3.1 Backup Modes

A backup is a copy of a file to off-line storage. Backups are important because they allow you to retrieve previous generations of a file even if it has been modified, damaged or deleted from your on-line directory. Because of the critical nature of many files, you need to copy the files to tape fairly often to:

• allow for recovery from a disaster
• provide for audits and legal requirements
• free up space on the on-line disk

The type of backup job is specified by the MANAGER when he creates the backup job. At most sites, the MANAGER will set up daily incremental backups and weekly and/or monthly full backups. Unloading backups might be scheduled daily, weekly, monthly or yearly depending on the site. Check with your MANAGER to learn the schedule of backups at your site.

In addition to standard Full and Incremental backups of on-line media, backups may be performed on remote nodes incorporating VMS clusters, PC networks and a variety of servers all to a central VMS device. Agent NT and Agent UNIX backup modes enable backups of remote nodes to remote backup devices.

Each BACKUP job in the BCKMGR system is defined by a set of attributes that describes what is to be backed up and how to do the back up. These attributes can be grouped as follows:

• What disk or files to back up. This is the parameter list. These disks or files can be on the local system or on a remote system.
• How to do the back up and conditions to examine. This is the backup mode and optional job settings.
• How many and what type of removable media to use. This is the media type, counts and flags.
• Other control attributes. This is the job log setting, protection codes and user name.

One of the key attributes is the backup mode number. The backup mode controls how the backup operation is performed. Several predefined modes are provided with the system. Others can easily be added by the user as needed.

Table 2-1 below lists the various predefined mode numbers.

Table 2-1 Backup modes

	Standard		Scratch
Backup Type	Incremental	Full	Incremental	Full
On-line	2	3	4	5
Appending	13	14	15	16
Remote VMS	9	10	11	12
Remote PC	17	18	19	20
Remote NFS	21	22	23	24
Agent NT	25	25	25	25
Agent UNIX	26	26	26	26
Backup Type	Incremental	Full	After Image Journal
RDB	6	7	8

2.3.2 Overview of Backup modes

The various backup modes are summarized in the below list. Later sections will describe the various backup types in greater detail.

• Standard - Standard indicates that the system will instruct the operator which media are to be used. During backups the system will issue OPCOM messages identifying exactly which media are to be loaded and on what drives. This is most commonly used with robotic systems and/or manualy loaded drives.
• Scratch - Scratch indicates that the system will request the operator to mount a generic available medium. The operator selects from what is already known to be available a medium and loads it. The system will then dynamically adjust itself to verify and use the loaded medium. ¹ This is most commonly used with stacker types of automated tape handling systems.
• Incremental - An incremental backup job copies from on-line disk to the off-line media all files that have been modified or created since the last backup operation was performed. Incremental backups are typically fast and should be performed fairly often.
• Full - A full backup creates a full disk image backup job. It makes a copy of the entire on-line disk to the off-line media. This type of backup is fairly lengthy and is usually done at a moderate frequency.
• After Image Journal - An After Image Journal writes out the RDB journal file to off-line media.
• On-line (2, 3, 4 and 5) - An on-line media is a normally accessible and system mounted disk that can be backed up using standard VMS backup.
• Appending (13, 14, 15 and 16) - Appending backups add new savesets to the same media as the previous run of the job. The previous data is not overwritten. New volumes are selected at intervals.
• Remote VMS (9, 10, 11 and 12) - The Remote VMS backup mode uses the DeviceShare² utility. It allows a remote OpenVMS system to serve it's local disk drives out to other OpenVMS systems and be backed up.
  These modes automatically connect/disconnect and performs the backup of such disks. This utility also makes remote tape drives available. They can be used as a dynamic output device as described in the next chapter.
• Remote PC (17, 18, 19 and 20) - The Remote PC backup uses the LANUtil³ system. It allows your OpenVMS system to backup the hard drives in any PC on your LAN (Novell, Pathworks, or LANmanager). This utility also provides several other useful management features to assist in managing PC.
• Remote NFS (21, 22, 23 and 24) - The Remote NFS backups allows the backup job to connect to a remote UNIX, WindowsNT or OpenVMS NFS server and backup the disk drives in that server. These modes automatically connect/disconnect while performing the backup. The Remote NFS backup mode uses any of the available TCP/IP for OpenVMS packages. The packages that have been tested are TCPware⁴, MultiNet⁵ and TCP/IP Services (or UCX)⁶.
• Agent NT (25) The Agent NT backup determines what media to use and then instigates a backup job on the remote NT system. This job would backup disk drives in the NT system to a tape drive attached to the NT system. Once the remote job completes usage information is collected and integrated back into the BCKMGR database.
• Agent UNIX (26) The Agent UNIX backup determines what media to use and then instigates a backup job on the remote UNIX system. This job would backup disk drives in the UNIX system to a tape drive attached to the UNIX system. Once the remote job completes usage information is collected and integrated back into the BCKMGR database.
• RDB (6, 7 and 8) - An RDB backup is used to backup RDB databases either by area or completely.

2.4 Designating Backup modes

While the backup mode number determines the type of backup that will be performed, the parameters in the parameter list must be correctly designated for the job to correctly execute. The parameters are dependent on the backup mode.

For instance, for an Agent NT backup of a remote Windows NT Workstation you need to have the Task/Agent Software installed and designate the backup mode as 25. The location of the NT devices and/or directories can then be designated as follows:

parameter(6) = "C:\WINDOWS" parameter(6) = "C:\SCU" parameter(6) = "C:\SCSI" parameter(7) = "D:\OFFICE97" parameter(8) = "e:\lotus"

The parameter designation of other backup modes is explained in the following sections:

2.4.1 On-line Backups

An On-line backup will process any disk that is mounted system wide and ready to be accessed. If this is not the case then an appropriate command file must be executed before the disk is referenced to bring it on-line. It can be put in using the "@" syntax discussed earlier.

Each time the job runs a new medium is used and initialized. The output can span any number of media. A typical parameter list for such job is:

parameter(1) = "DISK$ISE0:" parameter(2) = "DISK$ISE2:[SYSMGR]" parameter(4) = "DISK$ISE4:[SRC]SPECIAL.DAT"

2.4.2 Appending Backup

The appending mode adds to the end of the medium that was used last time. The appending mode is best suited where the output medium capacity greatly exceeds the needed capacity to do the backup. If, for example, your entire weeks incremental backups could fit on one cartridge then this mode is ideal. At intervals a new output medium is started. Two types of intervals are available they are "weekly" and "arbitrary".

The weekly interval allows you to specify which day is the last day to use the current medium. For example, to end the current medium on tuesdays and start a new one every wednesday a typical parameter list is given below:

parameter(1) = "+DAY_OVER := TUESDAY" parameter(6) = "DISK$ISE0:" parameter(7) = "DISK$ISE2:[SYSMGR]" parameter(9) = "DISK$ISE4:[SRC]SPECIAL.DAT"

2.4.2.2 Arbitrary interval

The arbitrary mode allows you to specify how many appends to do before starting a new medium. For example, to append to the current medium 10 times and on 11th start a new one, a typical parameter list would appear as follows:

parameter(1) = "+GROUP_MAX := 10" parameter(1) = "DISK$ISE0:" parameter(2) = "DISK$ISE2:[SYSMGR]" parameter(4) = "DISK$ISE4:[SRC]SPECIAL.DAT"

2.4.3 Remote VMS Backup

The Remote VMS backup mode can back up disks on a remote OpenVMS system by using the DeviceShare ⁸ utility. DeviceShare allows a remote system to serve it's local disk drives and/or tape drives over to the local system. This makes the remote disk drive and/or tape drive available to the local system. The node names of the remote systems needs to be specified before listing the disk drives on that system. A sample parameter list is as follows:

parameter(1) = "+BCK_NODE := ISE" parameter(1) = "DISK$ISE0:" parameter(2) = "DISK$ISE2:[SYSMGR]" parameter(4) = "DISK$ISE4:[SRC]SPECIAL.DAT" parameter(7) = "+BCK_NODE := ALPHA" parameter(8) = "DISK$ALPHA0:" parameter(9) = "DISK$ALPHA1:"

The backup will make a private connection to each remote disk before issuing the BACKUP command. When the BACKUP command is done the connection is terminated. The disk names used must be known to DeviceShare.

2.4.4 Remote PC Backup

The Remote PC mode can backup all the PC's in your LAN using the LANUtil ⁹ utility. The main feature of this utility is to provide access to the hard drives inside the PC to the VMS system in a non-intrusive manner.

This feature is used by this backup mode. There are several other very useful functions provided by the LANutil package. Please refer to the LANutil documentation for more information.

This procedure expects each parameter to establish the source node and disk drive to backup from. A sample of what can be on the parameter list is given below.

parameter(1) = "BIRCH::C:" parameter(2) = "MAPLE::C:[DOS.TEMP]" parameter(3) = "SPRUCE::C:[DOS.TEMP]AUTOEXEC.BAT"

Each parameter completely specifies the path to the file. The node name is included on each line. Alternately the path can be specified using the DOS file naming conventions. The above list specified using the DOS file format appears below:

parameter(1) = "MAPLE\C" parameter(2) = "MAPLE\C\DOS\" parameter(3) = "MAPLE\C\DOS\TEMP\AUTOEXEC.BAT"