This document provides an overview of the history and development of Ceph, an open-source distributed storage system. It discusses Sage Weil's initial research that led to Ceph's creation, the incubation of Ceph at DreamHost, the launch of Inktank to support Ceph's development and adoption, and the current state of Ceph including its growing community and usage in production deployments. It also outlines Weil's vision for Ceph's future, including improving governance, adding new technologies like tiering and erasure coding, and expanding its role in areas like big data and the enterprise storage market.

1. Building Tomorrow's Ceph
Sage Weil

9. Research beginnings
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11. UCSC research grant
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“Petascale object storage”
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DOE: LANL, LLNL, Sandia
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Scalability
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Reliability
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Performance
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Raw IO bandwidth, metadata ops/sec
HPC file system workloads
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Thousands of clients writing to same file, directory

12. Distributed metadata management
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Innovative design
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Subtree-based partitioning for locality, efficiency
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Dynamically adapt to current workload
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Embedded inodes
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Prototype simulator in Java (2004)
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First line of Ceph code
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Summer internship at LLNL
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High security national lab environment
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Could write anything, as long as it was OSS

13. The rest of Ceph
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RADOS – distributed object storage cluster (2005)
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EBOFS – local object storage (2004/2006)
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CRUSH – hashing for the real world (2005)
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Paxos monitors – cluster consensus (2006)
→ emphasis on consistent, reliable storage
→ scale by pushing intelligence to the edges
→ a different but compelling architecture

15. Industry black hole
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Many large storage vendors
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Proprietary solutions that don't scale well
Few open source alternatives (2006)
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Limited community and architecture (Lustre)
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Very limited scale, or
No enterprise feature sets (snapshots, quotas)
PhD grads all built interesting systems...
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...and then went to work for Netapp, DDN, EMC, Veritas.
They want you, not your project

16. A different path
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Change the world with open source
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Do what Linux did to Solaris, Irix, Ultrix, etc.
What could go wrong?
License
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GPL, BSD...
LGPL: share changes, okay to link to proprietary code
Avoid unsavory practices
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Dual licensing
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Copyright assignment

17. Incubation
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19. DreamHost!
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Move back to LA, continue hacking
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Hired a few developers
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Pure development
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No deliverables

20. Ambitious feature set
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Native Linux kernel client (2007-)
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Per-directory snapshots (2008)
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Recursive accounting (2008)
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Object classes (2009)
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librados (2009)
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radosgw (2009)
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strong authentication (2009)
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RBD: rados block device (2010)

21. The kernel client
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ceph-fuse was limited, not very fast
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Build native Linux kernel implementation
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Began attending Linux file system developer events (LSF)
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Early words of encouragement from ex-Lustre devs
Engage Linux fs developer community as peer
Initial attempts merge rejected by Linus
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Not sufficient evidence of user demand
A few fans and would-be users chimed in...
Eventually merged for v2.6.34 (early 2010)

22. Part of a larger ecosystem
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Ceph need not solve all problems as monolithic stack
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Replaced ebofs object file system with btrfs
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Avoid reinventing the wheel
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Robust, well-supported, well optimized
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Kernel-level cache management
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Same design goals
Copy-on-write, checksumming, other goodness
Contributed some early functionality
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Cloning files
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Async snapshots

23. Budding community
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#ceph on irc.oftc.net, ceph-devel@vger.kernel.org
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Many interested users
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A few developers
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Many fans
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Too unstable for any real deployments
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Still mostly focused on right architecture and technical
solutions

24. Road to product
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DreamHost decides to build an S3-compatible object
storage service with Ceph
Stability
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Focus on core RADOS, RBD, radosgw
Paying back some technical debt
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Build testing automation
Code review!
Expand engineering team

25. The reality
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Growing incoming commercial interest
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Early attempts from organizations large and small
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Difficult to engage with a web hosting company
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No means to support commercial deployments
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Project needed a company to back it
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Build and test a product
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Fund the engineering effort
Support users
Bryan built a framework to spin out of DreamHost

26. Launch
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28. Do it right
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How do we build a strong open source company?
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How do we build a strong open source community?
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Models?
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RedHat, Cloudera, MySQL, Canonical, …
Initial funding from DreamHost, Mark Shuttleworth

29. Goals
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A stable Ceph release for production deployment
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DreamObjects
Lay foundation for widespread adoption
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Platform support (Ubuntu, Redhat, SuSE)
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Documentation
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Build and test infrastructure
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Build a sales and support organization
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Expand engineering organization

30. Branding
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Early decision to engage professional agency
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MetaDesign
Terms like
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“Brand core”
“Design system”
Project vs Company
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Shared / Separate / Shared core
Inktank != Ceph
Aspirational messaging: The Future of Storage

31. Slick graphics
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broken powerpoint template
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32. Today: adoption
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34. Traction
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Too many production deployments to count
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We don't know about most of them!
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Too many customers (for me) to count
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Growing partner list
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Lots of inbound
Lots of press and buzz

35. Quality
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Increased adoption means increased demands on robust
testing
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Across multiple platforms
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Include platforms we don't like
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Upgrades
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Rolling upgrades
Inter-version compatibility
Expanding user community + less noise about bugs = a
good sign

36. Developer community
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Significant external contributors
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First-class feature contributions from contributors
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Non-Inktank participants in daily Inktank stand-ups
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External access to build/test lab infrastructure
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Common toolset
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Email (kernel.org)
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Github
IRC (oftc.net)
Linux distros

37. CDS: Ceph Developer Summit
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Community process for building project roadmap
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100% online
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Google hangouts
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Wikis
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Etherpad
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First was this Spring, second is next week
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Great feedback, growing participation
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Indoctrinating our own developers to an open
development model

38. The Future
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39. Governance
How do we strengthen the project community?
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2014 is the year
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Might formally acknowledge my role as BDL
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Recognized project leads
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RBD, RGW, RADOS, CephFS)
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Formalize processes around CDS, community roadmap
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External foundation?

40. Technical roadmap
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How do we reach new use-cases and users
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How do we better satisfy existing users
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How do we ensure Ceph can succeed in enough markets
for Inktank to thrive
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Enough breadth to expand and grow the community
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Enough focus to do well

41. Tiering
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Client side caches are great, but only buy so much.
Can we separate hot and cold data onto different storage
devices?
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Cache pools: promote hot objects from an existing pool into a fast
(e.g., FusionIO) pool
Cold pools: demote cold data to a slow, archival pool (e.g.,
erasure coding)
How do you identify what is hot and cold?
Common in enterprise solutions; not found in open source
scale-out systems
→ key topic at CDS next week

42. Erasure coding
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Replication for redundancy is flexible and fast
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For larger clusters, it can be expensive
Storage
overhead
3x replication
Repair
traffic
MTTDL
(days)
1x
2.3 E10
RS (10, 4)
1.4x
10x
3.3 E13
LRC (10, 6, 5)
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3x
1.6x
5x
1.2 E15
Erasure coded data is hard to modify, but ideal for cold or
read-only objects
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Cold storage tiering
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Will be used directly by radosgw

43. Multi-datacenter, geo-replication
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Ceph was originally designed for single DC clusters
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Synchronous replication
Strong consistency
Growing demand
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Enterprise: disaster recovery
ISPs: replication data across sites for locality
Two strategies:
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use-case specific: radosgw, RBD
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low-level capability in RADOS

44. RGW: Multi-site and async replication
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Multi-site, multi-cluster
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Zones: radosgw sub-cluster(s) within a region
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Regions: east coast, west coast, etc.
Can federate across same or multiple Ceph clusters
Sync user and bucket metadata across regions
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Global bucket/user namespace, like S3
Synchronize objects across zones
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Within the same region
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Across regions
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Admin control over which zones are master/slave

45. RBD: simple DR via snapshots
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Simple backup capability
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Based on block device snapshots
Efficiently mirror changes between consecutive snapshots across
clusters
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Now supported/orchestrated by OpenStack
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Good for coarse synchronization (e.g., hours)
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Not real-time

46. Async replication in RADOS
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One implementation to capture multiple use-cases
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RBD, CephFS, RGW, … RADOS
A harder problem
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Scalable: 1000s OSDs → 1000s of OSDs
Point-in-time consistency
Three challenges
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Infer a partial ordering of events in the cluster
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Maintain a stable timeline to stream from
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either checkpoints or event stream
Coordinated roll-forward at destination
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do not apply any update until we know we have everything that
happened before it

47. CephFS
→ This is where it all started – let's get there
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Today
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QA coverage and bug squashing continues
NFS and CIFS now large complete and robust
Need
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Directory fragmentation
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Snapshots
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Multi-MDS
QA investment
Amazing community effort

48. The larger ecosystem

49. Big data
When will be stop talking about MapReduce?
Why is “big data” built on such a lame storage model?
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Move computation to the data
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Evangelize RADOS classes
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librados case studies and proof points
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Build a general purpose compute and storage platform

50. The enterprise
How do we pay for all our toys?
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Support legacy and transitional interfaces
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iSCSI, NFS, pNFS, CIFS
Vmware, Hyper-v
Identify the beachhead use-cases
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Only takes one use-case to get in the door
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Earn others later
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Single platform – shared storage resource
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Bottom-up: earn respect of engineers and admins
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Top-down: strong brand and compelling product

51. Why we can beat the old guard
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It is hard to compete with free and open source software
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Unbeatable value proposition
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Ultimately a more efficient development model
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It is hard to manufacture community
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Strong foundational architecture
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Native protocols, Linux kernel support
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Unencumbered by legacy protocols like NFS
Move beyond traditional client/server model
Ongoing paradigm shift
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Software defined infrastructure, data center

52. Thank you, and Welcome!