Difference between revisions of "Ploop/Limits"

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(created)
 
m (fix ploop v2 size in PB)
Line 4: Line 4:
 
* Image size:
 
* Image size:
 
** ploop v1: 2 TB minus 1 MB
 
** ploop v1: 2 TB minus 1 MB
** ploop v2: 2 PB (4096 TB) minus 1 MB
+
** ploop v2: 4 PB (4096 TB) minus 1 MB
 
* Inner ext4 file system size: currently set to 16 TB
 
* Inner ext4 file system size: currently set to 16 TB
  

Revision as of 00:52, 30 July 2014

Ploop images has the following limits:

  • Number of snapshots: 126
  • Image size:
    • ploop v1: 2 TB minus 1 MB
    • ploop v2: 4 PB (4096 TB) minus 1 MB
  • Inner ext4 file system size: currently set to 16 TB

Conversion

Use ploop convert tool to convert from ploop v1 to ploop v2 image.


Internals

Ploop v1 image size limitation comes from the fact that unsigned 32 bit integer is used to store sector address inside the ploop image. Therefore the maximum number of sectors is (u32)-1, which is 4294967295. As sector size is 512 bytes, 4294967295 sectors are equal to 2 terabytes. From that number, we should subtract 1 megabyte, as first 1MB of image is used for translation table.