Feedback on immutability

florent

@rtjdamen for the immutability to be useful, the full chain must be immutable and must never be out of immutability

the merge process can't lift/ put back the immutability , and increasing synchronization between process will extend the attack surface.

immutability duration must be longer than or equal to 2 time the full backup interval -1
the retention must be strictly longer than the immutability .

for example, if you have a full backup interval of 7 a retention of 14 and immutability duration of 13 , key backup are K, delta are D. Immutable backup are in bold . unprotected chain are ~~striked~~

K~~DDDDDD~~KDDDDDD worst case, only one full chain protected
K~~DDDDD~~KDDDDDDK
K~~DDDD~~KDDDDDDKD
K~~DDD~~KDDDDDDKDD
KDDKDDDDDDKDDD
KDKDDDDDDKDDDD
KKDDDDDDKDDDDD best case almost 2 full chain protected

rtjdamen

@florent so this does mean it will never work when a forever incremental is used?

florent

@rtjdamen said in Feedback on immutability:

@florent so this does mean it will never work when a forever incremental is used?

you can't have a immutable forever backup without having a infinite length, and an infinite

It may be possible only if we release the constraints.
The immutable script could release the immutability , merge the disks, but that means : the immutability will be lifted from time to time, and the responsibilities of the immutability script will be greater, and we'll need a way to track the vhd to merge and transmit the information to the immutability script