The backup window can be initiated from multiple places in the Platform interface including the Platform Space screen, the Storage Group Screen and the Search Results Screen.
Source to Backup – This header in the window shows either the Platform Space to backup or a list of files. When showing the files, the system will only show the beginning list of files. Not all files will be listed.
Selected File Size – The total space of the files/folders selected will be listed. This is the amount of space that will be copied to the tape.
Backup Type – This allows the operator to select a Full Backup or an Incremental Backup type. See the definition of Full and Incremental Backups above.
Tape Drive – Selecting the tape drive allows the user to choose which tape drive the backup will use. The tape drive can be a standalone drive or an automation drive in a tape library. After selecting the tape drive, the system will display information about the current tape including the approximate space available.
In this example, the tape drive has an empty 2.5TB LTO6 tape in the drive.
File Verification (MD5 Checksum) – If selected, during the file backup process, the system will perform an MD5 checksum process on each file. See File Verification below for details.
Priority – The Priority field allows the operator to determine the task queue priority of the job. If tasks are queued in the task system, the will be run in priority order. By default, tasks go in as medium priority. This allows the operator to schedule a job with high priority which will run before any medium tasks in the queue.
Schedule – The task scheduling options allow the operator to have the task start immediately or at a future time. The system will also allow the backup to be run on a recurring schedule. See Task Scheduling Options in the Task section for more details.
After clicking on the Okay button, the system will submit the backup job to the task system and it will start when the tape drive is available.
File Verification (MD5 Checksum)
When this option is selected, the system will perform an MD5 checksum hash on each file before it is written to tape and then write the hash result to the catalog. After all files have been written to tape, the system will rewind the tape and read each file from tape, rehash the file and compare it to the hash in the database catalog. If all MD5 hash results match, the backup or archive is successful. If any files do not hash to the same number, the system will fail the backup or archive operation.
It is important to note that the MD5 process can add significant time to the backup process. Therefore, the administrator must weigh the benefit of verification against the additional backup time. Because of the way the Platform performs MD5 checksum, each backup essentially performs a backup and a restore operation. Therefore, the time required is at least double a regular backup. Additionally, large files that are backed up using MD5 checksum can take a significant amount of time to hash the file.
If the ‘Allow Tape Spanning’ Configuration option is not turned on and the system determines that total space being backed up is greater than the amount of space available on the tape cartridge selected, the operator will get a warning when attempting to submit the job. Because of tape compression algorithms, Platform cannot guarantee that the space will or will not fit on the tape.
When the operator requests a ‘Full Backup’, the system will copy every file in the source list to the tape drive. Additionally, during a Full Backup operation, the system will reset the ‘archive’ flag on each file. This approach allows the incremental backup (listed below) to know which files to backup since that last full backup occurred.
Incremental backups search the source list (Storage Group, Platform Space or specific list of files) to see if any files have been modified since the last full backup. This is especially useful in video environments since the actual source video files rarely change. If any files have changed since the original ‘Full Backup’, they will then be copied during the incremental backup job. If an incremental backup job is requested and no files have changed, no updates will be made to the tape.