ACM Transactions on Computer Systems (TOCS)
The design and implementation of the 4.4BSD operating system
The design and implementation of the 4.4BSD operating system
Stackable design of file systems
Stackable design of file systems
Soft updates: a technique for eliminating most synchronous writes in the fast filesystem
ATEC '99 Proceedings of the annual conference on USENIX Annual Technical Conference
| Hi-index | 0.00 |
I have recently developed DMFS, a Data Migration File System, for NetBSD[1]. This file system provides kernel support for the data migration system being developed by my research group at NASA/Ames. The file system utilizes an underlying file store to provide the file backing, and coordinates user and system access to the files. It stores its internal metadata in a flat file, which resides on a separate file system. This paper will first describe our data migration system to provide a context for DMFS, then it will describe DMFS. I also will describe the changes to NetBSD needed to make DMFS work. Then I will give an overview of the file archival and restoration procedures, and describe how some typical user actions are modified by DMFS. Lastly, I will present simple performance measurements which indicate that there is little performance loss due to the use of the DMFS layer.