NASD, GoogleFS, Farsite

Readings

Questions

What were the target environments for these filesystems? How did these environments shape their assumptions?
What are the key ideas behind each filesystem?
What are the strengths and weaknesses of each design?
What are the strengths and weaknesses of each implementation?
Which system is best suited for today's Internet? How about tomorrow's?

Questions for NASD

Is giving direct access between client and drive a good idea?
Are there substantial advantages in storing variable-length objects over fixed-sized blocks?
Is putting the filesystem on the drive a good idea? Should more control and awareness be given to hardware devices?
What are the strengths and weaknesses of the capability-based cryptography which NASD makes use of?

Questions for GoogleFS

How does the Google file system implement security?

- Doesn't

Is using a central server (point of access) a good design decision?

-It certainly works -Makes administration easier -As long as redundant and fast, why bother with the hassle of synchronization?

Is removing random writes a good idea?

-They didn't actually remove it, but it is horribly inneficient -BigTable specifically reduces the instances of random write and implements a way to append the same information

Is the speedup attained by GFS's record-append method worth the sacrifice of Application overhead?

-Needing to manage duplication yourself -Guaranteed access to specific offsets, which helps consistency, though wastes space

Questions for Farsite

Byzantine fault tolerance?
How similar and different compared to OceanStore?
What's up with the file lease mechanism?

Questions for Farsite retrospective

If using different programming methods... how does this file-system work given different programming models
Details of Byzantine fault tolerance