So I'm tinkering around with ZFS on linux and zrep. I've got 2 VMs on my laptop and I'm running zrep and synchronizing the contents of one filesystem to another.
One unexpected situation is this: If I'm on the "slave" -- the box that's receiving the data -- and I'm continuously reading the contents of a file (such as with sum), if the file is rapidly changing on the master I will get an Input/output error on the slave as the snapshot is getting applied. This does not happen if I'm continuously reading a file that isn't changing in the snapshot.
To be clear -- the "sum" program or any other standard userland program that is reading the changing file on the target filesystem will periodically get an Input/output error and crash.
The ZFS replication itself works correctly -- zrep is just a nice tool for managing the replication process.
I'm a little confused at this behavior -- will reads of files that get updated when a ZFS snapshot is applied cause read errors, or is this a bug in ZFS on linux?