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Scanning Overview

A scan traverses a file system and records, in the StorCycle database, information associated with the directories and files it encounters. A scan can start either at the root of a Storage Location or at a sub-directory of a Storage Location depending on parameters set in the scan project. From the starting directory, the scan traverses all sub-directories beneath it. Once a scan completes, categorization information (age and size of files), for each directory with changes since the last scan of that directory, is updated in the StorCycle database so that you can determine what data to migrate / store based on age and size attributes.

Note: The examples in this section are representations only. The StorCycle solution does not provide reports with similar information.

Scanning from the Root

A scan from the root traverses all sub-directories in the Storage Location. If data in a directory has changed since the last time the directory was scanned, the information for the data in the directory is updated in the StorCycle database and the scan histograms. Scanning from the root ensures that the information for all sub-directories is up to date, but it may take a long time.

A scan starting from the root directory provides the following:

Note: When the scan completes, histograms for previous root scans and sub-directory scans for sub-directories traversed by this root scan are updated with the data from the new scan.

Figure 65 An example scan from the root.

View the histogram, showing amount of data by age and file size, by clicking Complete next to the scan job in the Job State column of the Scan Jobs pane of the Scan screen. It can also be viewed in the Migrate / Store wizard once the working directory is selected.

Scanning from a Sub-Directory

A scan from a sub-directory traverses all sub-directories below the directory selected. If data in a directory has changed since the last time the directory was scanned, the information for the data in the directory is updated in the StorCycle database and histograms for previous scans of parent directories are updated with the new data. A sub-directory scan takes less time than a root scan, but does not update all branches of the storage location.

Using the same Storage Location from the last example, a scan starting from the Movies directory traverses and updates the sub-directories shown below:

Figure 66 An example scan from a sub-directory.

View the histogram, showing amount of data by age and file size, for the Movies directory by clicking Complete next to this scan job in the Job State column of the Scan Jobs pane of the Scan screen.

View the histogram for the updated root scan by clicking Complete next to the root scan job in the Job State column of the Scan Jobs pane of the Scan screen.

If the Star Wars® files are deleted from the Movies directory, a subsequent scan of the Movies directory updates the root scan as follows.

Notes: 

• This scan updates the parent directory's scan data.
• Old scan data is not re-classified as time passes. What is in the 0 to 30 day category stays there even if enough time has passed that it is now older than 30 days.
• Although this scan updates the data for the root scan, the date of the root scan does not change.

Figure 67 Scan update after data deletion.

If the Avengers files are moved from the Movies directory to the TV directory, a scan starting from the Movies directory updates the root scan as follows.

Notes: 

• Since the scan started with the Movies sub-directory, it only knows that Avengers is not under Movies any longer. It does not know that it is under TV. The full scan updates to show less data than the Storage Location actually contains. The difference can be corrected by scanning the TV directory or by scanning the root.
• Although this scan updates the data for the root scan, the date of the root scan does not change.

Figure 68 Scan update after data move.

A Migrate / Store Job’s Effect on Scan Data

The Migrate / Store wizard shows the latest scan graph for the directory selected as long as a previous root or sub-directory scan included that directory. As shown in Example 4, the latest scan may not be correct. If Use Last Scan is selected in the Migrate / Store wizard, the Avengers data will not be considered for Migrating / Storing. To make sure that the correct data is used, select Scan Before Migrate / Store.

Notes: 

• If Scan Before Migrate / Store is selected:
• The time required to complete the migrate / store job may increase by a significant amount.
• If Use Last Scan is selected:
• Only files present in the directory when the prior scan executed are considered for migration. If the prior scan was for a sub-directory of the working directory, only files in the sub-directory are considered for migration.
• The current size and age of the file are considered against the selection criteria when determining files to migrate / store.

When the Migrate / Store wizard moves data, it updates all of the directory category totals and the file information for the moved files in the database. This updates the histogram of the scan data for all scans including the affected directories. If the migrate / store used Use Last Scan, the database update does not include adding files that were not in the previous scan.

Notes: 

• Scan data is not updated after a restore. Similar to adding data to a directory, a new scan, from the root or a sub-directory is required to update the scan results after a restore.
• If you restore objects to their original location, they are not included in future scan data because they are not eligible to be migrated / stored.

If 30 days after executing Example 4, you choose to migrate / store all files greater than 100 GiB and greater than 6 Months old and select Use Last Scan, the database updates as shown after the migrate / store.

Notes: 

• The Avengers files were not considered for the migrate / store because they were not included in the previous scan.
• The amount of data greater than 6 months old has increased because the Friends files that were previously greater than 90 days have aged to be greater than 6 months.

Figure 69 Scan update after a migrate / store.

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