If one tries to give translator "write-behind" option "cache-size" a value less
than 128KB - it results in an error 

[write-behind.c:2511:init] aggregate-size(2048) cannot be more than window-size(131072)




>> This message is inherently wrong as we can see 2048 is less than 131072.



Can be easily reproduced giving cache-size option in the write-behind vol-specs.