6,534
edits
Changes
fix a link, fix a typo; add a note about N/M
* Image consists of cluster blocks (default cluster block size is 1 MB).
* First there are some cluster blocks with BAT (Block Allocation Table), then there are some cluster blocks with data.
* First 64 bytes of the first cluster blocks block is a header, described at in [httphttps://gitsrc.openvz.org/?p=projects/OVZL/repos/ploop;a=blob;f=/browse/include/ploop1_image.h ploop1_image.h]
* The rest of BAT is just an array of 4 byte slots.
* If a slot N contains value M, then a request to a cluster-block N of a /dev/ploopXXX device is redirected to a cluster-block M in an image file. N is counted from 0, while M is counted from 1 (0 means block is not yet allocated).
For the rest of the story, see sources.
[[Category: Storage]]
