DRBD 8.2.0, released today, includes a much requested new
feature, embodied in the new data-integrity-alg
configuration option: DRBD protocol level data integrity checksums.
A few months ago, some users alerted us to DRBD replication issues where DRBD supposedly “ate their data”, i.e. corrupted replicated data in transit. Eventually we traced those problems not to DRBD errors, but in fact to network drivers messing up TCP checksums or segmentation. Typically this was related to using either TCP segmentation offloading (TSO) or TCP checksum offloading. However, at the time DRBD had no way of detecting these errors — you would only find out if you switched over to your Secondary, only to find your data not having been replicated properly.
With DRBD 8.2.0, you can check the integrity of replicated data in transit. To that end, …
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