NFS Version 4 Workgroup Directions Remaining Work NFS Version 4 - - PowerPoint PPT Presentation

NFS Version 4 Workgroup Directions

Remaining Work

• NFS Version 4 Protocol

– Proposed Standard – Draft Standard – Apotheosis

• NFS Version 4 Implementation Choices

document – Spencer

The Implementations To Do

• Sun Java and Solaris (both)
• Hummingbird Communications (both)
• UMich OpenBSD and Linux (both)
• NetApp (server)
• EMC (server)
• OpenBSD by Rick Macklem (no bake-
• ff participation yet)

Implementations and IETF

• To move from Proposed to Draft Standard

– Minimum six months – Two independent interoperating implementations required

• Gated on IESG to Proposed Standard
• Question of the day: When is it safe to

ship?

Regarding Number of Implementations

• There are seven implementations in progress

– Rick Macklem is pursuing an eighth in OpenBSD

• There were only two implementations

complete on V3 protocol freeze

• Version 4 is doing great

– Implementation was not require to achieve Proposed Standard – so we are ahead of the game

When “to ship”?

• IETF guidelines say Draft Standard is stable

(and implies shippable)

• Proposed Standard is risky

– Subject to change following implementation experience

• Linux and OpenBSD source will be widely

available before Draft Standard

– Issue of how to control risk of old non-compliant implementation proliferation

Future Work

• Migration/replication
• SNMP MIB
• Name spaces/LDAP schemas
• Service Location Protocol
• Disconnected operation
• Performance issues in protocol
• Proxy cache support

Basics

• Not all work will necessarily involve

protocol changes

– Name space definition may be described via practices and informational RFC’s for example

• Minor revisioning support exists in NFS

Version 4

Migration and Replication

• Migration is the movement of a “file

system” from one server to another

– Useful only when transparent – Necessary even when not

• Replication is the creation of one or

more copies of a “file system”

NFS Version 4 “file system”

• Has a file system ID
• A closed set of unique “file ids” – aka

inodes☺

• A set of attributes associated with the

“file system”

• The basis for replication and migration?

Sticky issues

• fsid should define a “file system”

– Hard links exist within the file system

Migration/Replication

• NFS Version 4 defines client to server

interaction

– The volatile file handles allow cheesy solutions☺ – Hashed file names persist☺ – Undefined is server-to-server protocol

• Prior work for server-server

– AFS/DFS – rdist – rsync

Issues around M/R

• Efficient updates

– Minimize client suspension – Minimize transfer/updates

• Atomicity guarantees
• Replica integrity
• Read-only vs. write replication

– Write replication is harder, but…

Issues in M/R

• File level protocol vs. block level

protocol

– Multi-platform support

Practically speaking

• Re-charter working group to pursue

migration/replication (and other things)

• Charter new working group (please no)
• Timing?

– Don’t want to drain resources to complete core priorities

SNMP MIB

• Just work
• Informal, non-standard MIBs done in

past for Version 2 and 3?

• SNMP has not necessarily been

synonymous with mgmt

– Other avenues to pursue

Name spaces/LDAP schemas

• The “global” name space issue

– Service location?

• Implementation document to define

standards for naming?

– Practice best backed by mechanism to support it

Finding servers

• Finding resources (servers and file

systems) in the network

• Windows does this, AFS/DFS does this

Disconnected operation

• Coda and Windows 2000+ play in this

space

• Client implementation issue primarily?
• Minor protocol revision (error codes,

etc) for reconciliation

– Similar issues at 10,000 ft to multiple replica consistency and reconciliation

Performance

• NFS Version 4 involves more complex

marshalling and unmarshalling

– Coupled to more complicated error handling due to COMPUND operation – Implementations not sufficiently progressed to measure hit

• Protocol offload

– Sapuntzakis comments – Minor versioning for protocol tweaks?

Tuesday 1:00 – 2:00

• To discuss further migration and

replication

• Other futures

Follow up

• Contact area directors for guidance on future

work (distraction, focus, re-charter, etc.)

• Produce strawman for migration/replication
• Produce strawman for SNMP MIB
• Determine if other mgmt methods need

investigation

• Contact working group alias to determine

interest in future work