1. CS533 Concepts of Operating Systems Class 19 File System Reliability

2. 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?

3. 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?

4. 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