Comment 2 for bug 1886088

Wrote up a utility to check which CRC (if any) was used for provided fragments. Generally, if you're running liberasurecode 1.2.0 or later (which introduced metadata checksumming four years ago), fragment CRCs will either be "legacy" or "zlib". Sample several from different servers to establish a consensus. On older clusters, you may also encounter fragments where the CRC is "not set"; ignore these.

If all nodes are currently running liberasurecode>1.5.0, you are *not affected*; all nodes can already read fragments with either CRC. If nodes are running liberasurecode<=1.5.0 and

  * fragments have "zlib" CRCs, you are *not affected* and can upgrade safely.
  * fragments have "legacy" CRCs, you *are* affected and will need to upgrade carefully.

If you are running liberasurecode<=1.5.0 and there's a mix of "zlib" and "legacy" CRCs, more investigation is necessary.