- Data from disk was being read after bitrot verification to return
data for GetObject. Strictly speaking this does not guarantee bitrot
protection, as disks may return bad data even temporarily.
- This fix reads data from disk, verifies data for bitrot and then
returns data to the client directly.
HealFile() does not process the case when an empty file is lost in
some disks. Since, Reedsolomon erasure doesn't handle restoring empty
data, HealFile will create empty files similarly to CreateFile().
The reedsolomon library now avoids allocations during reconstruction.
This change exploits that to reduce memory allocs and GC preasure during
healing and reading.
This change removes the ReadFileWithVerify function from the
StorageAPI. The ReadFile was basically a redirection to ReadFileWithVerify.
This change removes the redirection and moves the logic of
ReadFileWithVerify directly into ReadFile.
This removes a lot of unnecessary code in all StorageAPI implementations.
Fixes#4946
* review: fix doc and typos
This change provides new implementations of the XL backend operations:
- create file
- read file
- heal file
Further this change adds table based tests for all three operations.
This affects also the bitrot algorithm integration. Algorithms are now
integrated in an idiomatic way (like crypto.Hash).
Fixes#4696Fixes#4649Fixes#4359
* Prevent unnecessary verification of parity blocks while reading erasure
coded file.
* Update klauspost/reedsolomon and just only reconstruct data blocks while
reading (prevent unnecessary parity block reconstruction)
* Remove Verification of (all) reconstructed Data and Parity blocks since
in our case we are protected by bit rot protection. And even if the
verification would fail (essentially impossible) there is no way to
definitively say whether the data is still correct or not, so this call
make no sense for our use case.
This is an enhancement to the XL/distributed-XL mode. FS mode is
unaffected.
The ReadFileWithVerify storage-layer call is similar to ReadFile with
the additional functionality of performing bit-rot checking. It
accepts additional parameters for a hashing algorithm to use and the
expected hex-encoded hash string.
This patch provides significant performance improvement because:
1. combines the step of reading the file (during
erasure-decoding/reconstruction) with bit-rot verification;
2. limits the number of file-reads; and
3. avoids transferring the file over the network for bit-rot
verification.
ReadFile API is implemented as ReadFileWithVerify with empty hashing
arguments.
Credits to AB and Harsha for the algorithmic improvement.
Fixes#4236.
