Add modified timestamp consistent check between ufs and alluxio.
When a file in the UFS replace to another file with the same size, the Alluxio never know it.
Thank you for your apply, PR-5677 is aim to resolve this issue through record the UFS file last modification timestamp when inode create, and compare the record value to UFS last modification timestamp when checkConsitency.
I think using the file md5 or sha is a good idea, but will we calculate the MD5 when checkConsistency? And Is it a easy way to get a file md5 or sha from UFS when every consistency check?