Dne 18.5.2018 v 01:36 Eric Wheeler napsal(a):
Hello all,
Is there a technical reason that DATA_DEV_BLOCK_SIZE_MIN_SECTORS is
limited to 64k?
I realize that the metadata limits the maximum mappable pool size, so it
needs to be bigger for big pools---but it is also the minimum COW size.
Looking at the code this is enforced in pool_ctr() but isn't used anywhere
else in the code. Is it strictly necessary to enforce this minimum?
Hi
Selection of 64k was chosen as compromise between used space for metadada,
locking contention, kernel memory usage and overall speed performance.
If there is a case, where using 4K chunks for snapshot is giving a major
advantage, there is still availability to use old snapshot target.
Regards
Zdenek
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