Many thanks for your response. One more question, In the case of a CRC mismatch how many times does it retry and does it raise any error logs in the kernel to see if it had a CRC mismatch or not? On Thu, Feb 11, 2021 at 3:05 PM Ilya Dryomov <idryomov@gmail.com> wrote:
On Thu, Feb 11, 2021 at 1:34 AM Seena Fallah <seenafallah@gmail.com> wrote:
Hi, I have a few questions about krbd on kernel 4.15
1. Does it support msgr v2? (If not which kernel supports msgr v2?)
No. Support for msgr2 has been merged into kernel 5.11, due to be released this weekend.
Note that the kernel client will only support revision 1 of the msgr2 protocol (also referred to as msgr2.1). The original msgr2 protocol has security, integrity and some general robustness issues that made it not conducive to bringing into the kernel.
msgr2.1 protocol was implemented in nautilus 14.2.11 and octopus 15.2.5, so if you want e.g. in-transit encryption with krbd, you will need at least those versions on the server side.
The original msgr2 protocol is considered deprecated.
2. If krbd is using msgr v1, does it checksum (CRC) the messages that it sends to see for example if the write is correct or not? and if it does checksums, If there were a problem in write how does it react to that? For example, does it raise I/O Error or retry or...?
Yes, it does. In case of a crc mismatch, the messenger will reset the session and the write will be retried automatically.
Thanks,
Ilya