Fast backup of partitions
Remark: The fast backup of partitions and disks can protect against malicous programs.
However, it is then necessary to store the backups separately so that they cannot be destroyed by the malicious program.
Overview:
Starting with Boot-US version 4 a fast backup of single partitions or whole disks is possible.
In particular the backup of true hidden partitions is quick and easy with Boot-US.
Boot-US recognizes the filesystem of FAT16/FAT32/exFAT, NTFS and Ext2/3/4 partitions, and thus can skip unoccupied sectors in the backup.
This feature can speed up the backup enormously.
Example:
The following hardware is used:
- Thinkpad X250 with CPU i5-5300U and 4 GB RAM
- Disk 1: SATA SSD, 500 GB, read and write speed approx. 470 MB/sec
- Disk 2: SATA SSD, 500 GB, read and write speed approx. 470 MB/sec
An Ext4 partition of size 155 GB will be saved to a file. The file resides on disk 2 on a NTFS partition.
This allows a simultanouos access to both disks.
The Ext4 partition is 8 percent full.
In the backup only the occupied sectors are taken into account, the data is saved compressed.
The following screenshot shows the throughput just before close before the end of the backup.
A physical throughput of 330 MB/sec can be seen.
That's slightly less than the maximum speed of the two SSDs, which is due to the frequent occurrence of short sequences of consecutively occupied sectors.
However, the effective throughput is 2900 MB/sec, which is almost 10 times faster.
The reason is that the unoccupied sectors are skipped.
The displayed values are averaged over 5 seconds, which explains the small deviation from the simple formula $progress/$elapsed_time.
With faster hardware, a correspondingly larger throughput would be expected.
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