Backup How

Performance Parameters

Media Utilization

Staging area holding disks are written in parallel. By the time the first completed DLE backup has been written to the media, many more DLEs backups may also be ready to be moved. This parameter sets the algorithm that determines the order in which the completed backup images are moved from holding disk to the backup media.

Only completed backup images on the holding disk are considered for moving; the ordering of the images can help in better utilization of backup media.

Options are:

• First: (Default value) First in - first out.
• Firstfit: The first backup image that will fit on the current media volume.
• Largest: The largest backup image first.
• Largestfit: The largest backup image that will fit on the current media volume.
• Smallest: The smallest backup image first.
• Last: Last in - first out.

Backup Order

Whenever two or more parallel streams need simultaneous access to the same media volume, there is a potential conflict: Which stream should be allowed to write first?

Using Backup Order, you can assign priority to each of the parallel backup processes, the number of which is determined by the value of the "Parallel Backups" field above.

The possible option choices and what they mean is indicated below:

• s -> smallest size first
• S -> biggest size first
• t -> smallest time first
• T -> biggest time first
• b -> smallest bandwidth first
• B -> biggest bandwidth first
• Try BTBTBTBTBTBT if holding disks have not been assigned a threshold (see below)

Example 1 :
A string like "sssS" which represents the priority order for four parallel backups indicates that
three dumpers will seek the smallest size hosts 
while one dumper will seek the biggest size host to backup.
Example 2 :
A string like 'BbsTt' indicates there are five parallel backup process of which:
One backup process(B) is looking for the Biggest Bandwidth occupying backups.
Another backup process(b) is looking for the smallest Bandwidth occupying backups.
Another backup process(s) is looking for the smallest size backups.
Another backup process(T) is looking for biggest Time occupying backups.
Another backup process(t) is looking for smallest Time occupying backups.

Server Parallel Backups

Sets the number of parallel data backups that are performed from the Amanda clients to the holding disk in a backup run. The default value is 10. How many parallel backups happen to the staging area/holding disk depends on

• CPU and Write speed on the Amanda server
• Network configuration between the Amanda server and Amanda client

Parallel Backup Clients

Sets the number of parallel backups performed from an Amanda client. The default value is 1, which specifies that all DLEs on a client are backed up sequentially.

If an Amanda client has sufficient CPU and network resources, multiple DLEs on the client could be backed up in parallel.

The port range to use on Amanda server to connect to clients. Amanda will use all the ports in the range that are not bound by another process or not reserved in the /etc/services file. You will have increase the range (or use different range) if you are increasing the value of Server Parallel Backups.

Time Outs and Notifications

Email address

Sets the e-mail address of the Amanda backup administrator. Though this is an optional parameter, it is important to set the Notification parameter to the email address(es) of the Amanda administrator. Amanda backup run notifications will be sent to the email address. The email address can be different from the email address set in the Admin page for a particular user. ZMC also provides content of the notification in the Report Summary page for the backup set. You can enter multiple email addresses separated by comma or white space characters.

The Mail User Agent (MUA) such as Mail should be configured on the Amanda server before any email can be sent. ZMC does not install or configure the MUA. Amanda uses /usr/bin/mail by default to send email notifications. To configure alternate mail program, please see Configuring Alternate Mail Program section.

Backup Estimate (per DLE/Backup Object)

Limits the amount of time the ZMC will spend on the first phase (Planning phase) of the backup process. The Amanda backup process first estimates backup size for each DLE configured in the backup set. The backup size estimation for all DLEs in the backup set is done in parallel.

Specify a time out (in Seconds) by which each Amanda client has to respond with a backup size estimate.

If the time out occurs for a particular DLE, that DLE will not be backed up during the backup run. Amanda will perform a full backup for the DLE in the next backup run.

The time out specified should take into account factors such as clients with limited network bandwidth, limited CPU, multiple DLEs on one host, and clients with large amounts of data to be backed up.

Some idea of the time being taken to perform size estimates can be had from the Monitor page where details of the current backup run are displayed. A much better idea can be had from the Report Timeline page where DLE-wise details are displayed.

If a DLE has timed out, it will be displayed in red. Other DLEs are displayed in green.

Verification

ZMC Backup What verifies the configuration of the client/Backup object that is being added or modified. The client verification is controlled by this time out.

The time out may be adjusted for clients with limited network bandwidth.

If the time out expires, the verification of the client fails.

This time out has no impact on the backup process. If the client is properly set up, it will be backed up.

The time out applies to all clients in the backup set.

No Data Sent

Limits the time (in Seconds) that the Amanda server will wait (during the backup data transfer phase) for a client to begin to respond to a backup request.

If data time out occurs for a client, the backup of all directories for the client is not done in the backup run. The directories on the client will be backed up in the next backup run.

The time out may be adjusted for clients with limited network bandwidth.

The time out applies to all clients in the backup set.

Configuring an Alternative Mail Program

By default, Amanda assumes the local mail program found during initial configuration will be used to send notifications. You may wish to override this. For example, if your site uses an SMTP server, you can configure Amanda to use that instead of the program found during initial configuration. Use the mailer directive in the amanda.conf file:

mailer mail_program_path

The mail program must be able to process messages using the syntax:

MAILER -s "subject" user < message_file