Hello Everyone,
I've just started using rsync to copy files from Windows NT RCS library to Stratus VOS (Posix like fauilt tolerant Mini system) as a shadow. I would also like to setup rsync to copy log or other process output files from VOS to an NT system. Some questions if anyone here can help:
1. is there any computational or disk IO difference between the rsync client and server (the one that does just the checksum on the block, vs the one that does rolling checksum). Given that I do not have as much cpu on the VOS machine, I would like the more expensive side to run on the Windows system. So I need to figure out who should run the daemon and who should push vs. pull.
2. is there a way for rsync to cache previous calculations on checksum, or be told that a particular file of regex filename starname is always appended to, so it does not read the entire file? Basically I have processes that constantly append to ann output file on VOS. I would like to mirror these onto the NT machine. However, I do not want to have rsync every few minutes read the entire file. Choices I see are:
a. tell rsync that the file is append mode, so it just picks up from the last block size on the other machine and goes forward
b. rsync is smart enough not to do this on its own
c. rsync can store cached checksum information
d. there is another option that tells rsync to do this that I missed.
e. there is an option to tell rsync to basically continue to read the file every X interval after it gets to the end without exiting.
3. expanding on option 2e. One possibility would be to run rsync for each file being synced and telling it to just sync to the end, then stay in memory, and look for file changes or try to read more blocks at the end (assuming another process is writing to it), and sync those new blocks. This would keep rsync from stopping and having to restart from the beginning. It may however, cause memory issues for large files if it keeps the whole checksum in memory?
Any ideas or other ways to get around this? Again, question 2/3 are for basically syncing open log files to another machine efficiently. There may be another tool out there for this that I'm not aware of, if so, please enlighten me so I can stay away.
Thanks in advance for any help.
