The Zebra Striped Network File System
John Henry Hartman
EECS Department
University of California, Berkeley
Technical Report No. UCB/CSD-95-867
1994
This dissertation presents a new network file system, called Zebra, that provides high performance file access and is highly available. Zebra stripes file data across its servers, so that multiple servers may participate in a file access and the file access bandwidth therefore scales with the number of servers. Zebra is also highly available because it stores parity information in the style of a RAID [Patterson88] disk array; this increases storage costs slightly but allows the system to continue operation even while a single storage server is unavailable.
Zebra is different from other striped network file systems in the way in which it stripes data. Instead of striping individual files (file-based striping), Zebra forms the data written by each client into an append-only log, which is then striped across the servers. In addition, the parity of each log is computed and stored as the log is striped. I call this form of striping log-based striping, and its operation is similar to that of a log-structured file system (LFS) [Rosenblum91]. Zebra can be thought of as a log-structured network file system: whereas LFS uses a log abstraction at the interface between a client and its servers. Striping logs, instead of files, simplifies Zebra's parity mechanism, reduces parity overhead, and allows clients to batch together small writes.
I have built a prototype implementation of Zebra in the Sprite operating system [Ousterhout88]. Measurements of the prototype show that Zebra provides 4-5 time the throughput of the standard Sprite file system or NFS for large files, and a 15-300% improvement for writing small files. The utilizations of the system resources indicate that the prototype can scale to support a maximum aggregate write bandwidth of 20 Mbytes/second, or about ten clients writing at their maximum rate.
Advisor: John K. Ousterhout
BibTeX citation:
@phdthesis{Hartman:CSD-95-867,
Author = {Hartman, John Henry},
Title = {The Zebra Striped Network File System},
School = {EECS Department, University of California, Berkeley},
Year = {1994},
Month = {Dec},
URL = {http://www.eecs.berkeley.edu/Pubs/TechRpts/1994/5596.html},
Number = {UCB/CSD-95-867}
}
EndNote citation:
%0 Thesis %A Hartman, John Henry %T The Zebra Striped Network File System %I EECS Department, University of California, Berkeley %D 1994 %@ UCB/CSD-95-867 %U http://www.eecs.berkeley.edu/Pubs/TechRpts/1994/5596.html %F Hartman:CSD-95-867