CS533 Concepts of Operating Systems

Class 19

File System Reliability

CS533 - Concepts of Operating Systems 2

Questions

How do mirroring and RAID-5 increase the reliability of file data?

o What kinds of failures can be tolerated?o Why might you choose mirroring over RAID-5?o Why might you choose RAID-5 over mirroring?

If a storage device migrates blocks dynamically between mirrored and RAID-5 storage, how can file system software keep track of where data is?

If the storage system is log-structured, does the file system above it need to be log-structured?

CS533 - Concepts of Operating Systems 3

Questions

Need file system software above HP AutoRAID concern itself with free-space management?

Would the system benefit from using a device interface at a higher level of abstraction?

o Why not implement the file abstraction at the device level?

o Why not implement versioning at the device level?o How can disk blocks be shared among versions of the

same file?

How can useful patterns and relationships be communicated from application to device level?

CS533 - Concepts of Operating Systems 4

What next?

No need to write reviews for the last set of papers!

Hand in your position papers next class Final will be a take home

o Shouldn’t take more than a couple of hours