nfusr is a userspace NFSv3 client built on top of libnfs and designed with four key goals: (1) allowing connections to multiple NFS servers for load balancing and high availability, (2) retrying spurious errors to improve reliability, (3) enabling quick iteration and easy upgrades through its modern C++ codebase, and (4) collecting client-side metrics to measure performance and reliability as experienced by users. The open source nfusr client aims to offer an improved alternative to the traditional kernel-based NFS client.

2. nfusr: Userspace NFSv3
Shreyas Siravara
Production Engineer @ Facebook

3. 1. Talk to many NFS servers, not just 1
2. Retry spurious errors
3. Iterate quickly, upgrade easily
4. Collect metrics & measure reliability
Why Userspace NFSv3
Why do we want a userspace NFSv3 client?

4. • FUSE based NFSv3 client
• Built on top of libnfs
• Modern C++
What is nfusr?

5. Why nfusr?
Multi-Server Support
Gluster
Volume
gNFSd
gNFSd
gNFSd
gNFSd
nfusr

6. Why nfusr?
Retry on Error
• Retries FOPs
• On idempotent FOPs only
• Retries hit a different NFS server
• Fewer spurious errors sent to the application
• Example: EROFS on temporary quorum loss

7. Why nfusr?
Client-side Metrics
• Reliability as perceived by the user
• Measure the client-side experience
• Latency and error rates
• Request sampling
WE ❤
METRICS

8. Why nfusr?
Operational Simplicity
• Simplicity with upgrades
• Eliminate the need to manage virtual IPs
• Remediate misbehaving mounts with ease
• Kill process, remount

9. Open Source
https://github.com/facebookincubator/nfusr