Why does the Partition Assistant keep adjusting my partition sizes?

Comments

• aiArtisan

  July 1 edited July 1

  Thank you Youda, for posting about this issue. You have 2 issues, 1 is I understand you want to shrink to an exact MB boundry, but it is changing that slightly.

  Your other issue is about empty space.
  

  "it creates up to 8 MB of unused space before my partition"

  I have seen many operating systems and applications create tiny empty spaces between partitions, even when it is not necessary. I have seen that for years on many Linuxes, many Windows installations, and USB stick creations. It is normal for a disk partitioning software from Windows or Linux to leave a tiny empty space in front or behind a partition, I don't know why it is done, but it is common.
  

  If that video is from someone else's PC, then please reply with a screenshot from your PC.

  Please email support to open a ticket about this.

  Tech Support
  [email protected]

  Partition Assistant General Help Topics
  https://www.diskpart.com/help/index.html
  
  Partition Assistant Manual
  https://www.diskpart.com/download/UserManual.pdf
  

  
  
• admin

  July 2

  @Youda008, 1. Sector and cluster alignment is performed when partitions are processed. The program automatically adjusts the start and end positions of partitions to ensure that partition boundaries are aligned to an integer multiple of the cluster. Usually several sectors form a cluster, and when the number of sectors adjusted is not enough to reach an integer number of clusters, the program will increase/decrease the number of sectors in order to reach an integer multiple of the clusters. So this may adjust the size to some strange number. 

  2. Regarding 4k alignment, the program may leave some unused space at the beginning of the partition to ensure that all subsequent partitions are aligned to 4k. This is because the starting position of the partition may not always be aligned exactly to the 4KB boundary, so some space needs to be set aside to ensure alignment.
• Youda008

  July 2 edited July 2

  Thank you for a reply, but i'm affraid i still don't understand.

  
  

  The clusters of SSDs usually have a size of 4096 bytes, which means a megabyte should always be an integer number of clusters. So if the beginning of the partition is aligned and i select an integer number of MBs, its end should also be aligned and no adjustment should be needed. On the contrary, numbers like 47.07, 54.91, 62.75 do not seem to be an integer number of blocks at all. What am i missing here?

  
  

  Also, 8 MBs space between partitions still does not make sense to me. If the program wants to ensure alignment to 4 KB boundary, then the empty space between partitions never needs to be bigger than 4 KB.
  

  
  

  After some more testing and calculations i found out that when creating new partition, both the "Unallocated space before" and "Partition size" are enforced to be a multiple of 7.84 or 7.85 MB, which is ~8028 KB and ~2007 clusters. Why 2007 and not 2000 for example? This number doesn't seem to make any sense.
  

  
  
  
  
  
  
  
• Youda008

  July 2 edited July 2

  After some more testing and calculations i found out that when creating new partition, both the "Unallocated space before" and "Partition size" are enforced to be a multiple of 7.84 or 7.85 MB (regardless of the "SSD Partition Alignment" setting, which is ~8028 KB and ~2007 clusters. Why 2007 and not 2000 for example? This number doesn't seem to make any sense.
  
• kjones120320

  July 23

  The Partition Assistant adjusts your partition sizes to optimize disk space and improve system performance. It reallocates space based on system requirements, application needs, and to ensure efficient storage use. If these changes aren't suitable for you, you can customize the settings to maintain your preferred partition setup.