7075: Acronis True Image Home 2010: Understanding Acronis Nonstop Backup

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Acronis Nonstop Backup first creates a snapshot of the protected partition and then saves file changes

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Description

For a general description of Acronis Nonstop Backup, please see Acronis Nonstop Backup in Acronis True Image Home 2010.

Here is how Acronis Nonstop Backup in Acronis True Image Home 2011 works:

  1. When started, the product does the following:
    • Creates a full disk image excluding all files on the protected partition. This ensures that when restored, the partition will be bootable;
    • Creates a full file backup of all files on the partition.
  2. Then a special Continuous Data Protection (CDP) driver is turned on. This CDP driver reads all requests to the protected partition and copies these to its data buffer.

    Every 5 minutes these requests (which constitute file changes) are flushed (i.e. saved) to the Acronis Nonstop Backup storage. Thus, one time slice is created, while the CDP driver keeps reading the requests.

    It is important to understand that since all the files were backed in their entirety at Step 1, Acronis Nonstop Backup every 5 minutes saves only the file changes, not the files themselves. This saves disk space. The changes are requests to the files done since the last slice was created. In other words, Acronis Nonstop Backup "compares" the latest slice with the one in progress and saves only the changes.

Should there be too many requests to be flushed, and Acronis Nonstop Backup is not able to flush them all in a five minute interval, the time stamp will still be created as the valid 5 minute point. This case, however, is rare.

Sample scenario

  1. All the requests are flushed by the time the 15 minute point is reached. A time slice for the 10 minute point is created;
  2. There is an overwhelming amount of requests in the time period between the 10 minute and 15 minute points. At the 15 minute point the product starts flushing these requests. By the time the 20 minute point is reached, not all the requests are flushed. The product keeps flushing the requests and finishes at 21 minutes. A 15 minute point is created.

    It is important to remember that the product flushes the requests and copies the new requests to its data buffer at the same time. Thus, no data is lost and the time points are created correctly. For example, in this sample scenario, you will have valid 10, 15, 20 and so on minute points.

If the scenario involves a reboot, which means that the CDP driver is off until the system boots, the whole procedure starts again from Step 1. This does not mean, however, that a new backup is kept in the storage - it is consolidated with the existing one, which saves space.

Backups older than 24 hours are automatically consolidated in such a way that Acronis True Image Home will keep daily backups for the last 30 days and weekly backups until all Nonstop Backup storage space is used. The consolidation will be performed every day between midnight and 01:00 AM. The first consolidation will take place after the Nonstop Backup works not less than 24 hours. If you turn off the Nonstop Backup for some time, the consolidation will start after you turn it on again.

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