Your SlideShare is downloading. ×
20101218 p nfs status
Upcoming SlideShare
Loading in...5

Thanks for flagging this SlideShare!

Oops! An error has occurred.

Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

20101218 p nfs status


Published on

Published in: Technology
1 Like
  • Be the first to comment

No Downloads
Total Views
On Slideshare
From Embeds
Number of Embeds
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

No notes for slide


  • 1. pNFS: Parallel NFS
  • 2. Agenda pNFS Technology Overview Timeline Future Work Discussions & Questions Page 2
  • 3. Traditional NFS limitations � Single NFS server bottleneck: limited bandwidth & CPU � Multiple NFS servers are separate storage islands NFS Page 3
  • 4. Proprietary Solutions � SAN (IBM, EMC, Sun) and Object (IBM, HP, Panasas) file systems: – Clients bypasses metadata server to access data – Each system is doing differently implementation � Scalable/cluster NFS servers: – Facilitate scalable aggregate load – Do not provide scalable/parallel bandwidth to a single file Page 4
  • 5. What Is pNFS? Metadata Server� pNFS protocol – NFSv4.1 pN FS� Storage access protocol Protocol C lient – File (NFSv4.1) Control Protocol – Block (FC, iSCSI, FCoE) – Object (OSD2)� Control protocol Storage Access – Implementation decision Protocol Data Servers Page 5
  • 6. pNFS Advantage� Distributed data access across the storage cluster� Reduce load on NFS server� I/O Acceleration Page 6
  • 7. pNFS Performance� Linear I/O increase� Client performance limitation is on backend� Numbers taken with EMC MPFS, from which pNFS block layout derives Page 7
  • 8. pNFS Related Standards� RFC 5661: NFSv4.1, including pNFS file layout� RFC 5662: NFSv4.1 XDR representation� RFC 5663: pNFS block/volume layout� RFC 5664: pNFS object operations Page 8
  • 9. Other NFSv4.1 Key Features� EOS (Exactly Once Semantics)� File and directory delegation� No more “silly rename”� Data retention� Session trunking and client ID trunking Page 9
  • 10. pNFS Timeline� 2004 — CMU, NetApp and Panasas drafted pNFS problem and requirement statements� 2005 — CITI, EMC, NetApp and Panasas drafted pNFS extensions� 2005 — NetApp and Sun demonstrated pNFS at Connectathon� 2005 — pNFS added to NFSv4.1 draft� 2006-2008 — specification baked – Bake-a-thons, Connectathon – 26 iterations of NFSv4.1/pNFS spec� 2009 — RFC submitted� 2010 — RFC published� 2010 — Fedora 10 includes pNFS server/client gits and rpms� 2010 — RHEL6.x is promised to have pNFS Page 10
  • 11. Industry Support� BlueArc � NetApp� CITI � Ohio SuperComputer Center� CMU � Panasas� EMC � Seagate� IBM � StorSpeed� LSI � Sun Microsystems (now Oracle) Page 11
  • 12. Linux pNFS Client� Applications transparency� Fewer support issues for storage vendors� Generic pNFS client with layout driver plugins Client Applications pNFS Kernel M odule Layout D river N F S v 4.1 S torage LayoutGet Protocol LayoutReturn pNFS Control Protocol Server Page 12
  • 13. pNFS Primitives� Layout – Describes how a file is distributed among storage� Segment – Each layout has one or more segments. A segment is a distribution pattern.� Device – Describes the storage (file server, backend block device, OSD data server)� Layout OPs – Layoutget, layoutreturn, layoutcommit, cb_layoutrecall Page 13
  • 14. Linux pNFS Client Driver API� struct pnfs_layoutdriver_type – layout driver specific functions (segment ops, layout ops)� struct pnfs_layout_hdr – generic layout header� struct pnfs_device – generic device� struct pnfs_layout_segment – generic layout segment Page 14
  • 15. Linux pNFS Merge Plan� End of 2010 – Linux 2.6.37 — Files pNFS client and server� Feb, 2011 – Linux 2.6.38 — Object pNFS client and server� May, 2011 – Linux 2.6.39 — Block pNFS client and server Page 15
  • 16. What Is Expected In NFSv4.x� File, Block, Object layout driver� Server side copy� Federated file system Page 16
  • 17. Open Issue – Layout stateid, open mode relationship Client Behavior Server Returns OPEN read-only open stateid1 LAYOUTGET with layout stateid1 IOMODE_READ CLOSE OPEN read-write open stateid2 LAYOUTGET with layout stateid1 IOMODE_READ using open stateid2 LAYOUTGET with IOMODE_RW NFS4ERR_OPENMODE using layout stateid1 Page 17
  • 18. Open Issues� Is LAYOUTRETURN still necessary for forgetful mode?� Slot id is required for every COMPOUND request, but idempotent non-modifying requests do not really need one� Security issue for block layout� Can File, Object and Block layouts co-exist in the same storage network? Page 18
  • 19. Page 19