Transcript Internet Backplane Protocol API and Applications

Mobile Management of
Network Files
Alex Bassi
Micah Beck
Terry Moore
Computer Science Department
University of Tennessee
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Logistical Networking
• Technology for shared network storage that
can scale in terms of
– the size of the user community,
– the aggregate quantity of storage that can be
allocated, and
– the breadth of distribution of service nodes
across network borders
• Parallels layered IP networking stack
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Bottom-up Design Philosophy
• The lowest globally accessible network
layer in the network storage stack should
– Enable scalable Internet-style resource sharing
– Expose underlying storage resources in order to
maximize freedom at higher levels
• Standard network storage systems fails in
some degree to satisfy one or both criteria.
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Internet Backplane Protocol
(IBP)
• Servers that make
allocation of primitive
“byte arrays” available
to clients
• Byte arrays are not
blocks (more abstract)
– Network capabilities
(primitive security)
– Variable extents
• Byte arrays are not
files (weaker
semantics)
– Size & duration are
limited
– “Volatile” allocations
– Best effort reliability
and availability
– No directory structure,
accounting
– No caching, replication
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The Logistical Networking Project
at the University of Tennessee
• Primary UT Investigators
• UT Graduate Students
– Micah Beck
– Wo Ling
– James S. Plank
– Yong
• UT Research Staff
– Xiang
– Alex Bassi
– Erica Fuentes
– Terry Moore
– Anthony Burton
• Funding
– DOE Next Generation Internet & SciDAC
– NSF Next Generation Software
Logistical Computation and Internetworking (LoCI) project w/ Birman,
Dongarra, Wolski
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Collaborating Projects
• Network Weather
Service (UCSB)
– Rich Wolski
– Martin Swany
• NetSolve (UT ICL)
– Jack Dongarra
– Michelle Miller
• L-Bone & LoFS (UT)
– James S. Plank
• Application Level
Scheduling (UCSD)
– Fran Birman
– Henri Casanova
– Graziano Obertelli
• Tamanoir
(Université Claude
Bernard Lyon 1 )
– Laurant Lefavre
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Building on IBP
• Many applications assume file semantics
– Unbounded size & duration
– High reliability & availability
– Caching & replication
• In a layered architecture, these are
implemented through aggregation and
additional intelligence at the next level
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Enter the exNode
• In the Unix file system, blocks are
aggregated into files using the intermediate
node data structure, or inode
• We implement file semantics on top of IBP
using the external node (exNode) data
structure
– Aggregation of IBP byte array allocations
– Additional metadata to enable management
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ExNode vs inode
IBP Allocations
the network
local system
capabilities
exNode
inode
user
kernel
block addresses
disk blocks
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The exNode is a Set
• A set of mappings and
associated metadata
• A mapping associates
a data extent and a
temporal extent with a
(set of) storage
resource(s).
• Minimal container API
– constructor &
destructor
– add mapping
– enumerate
• Lookup functions
– get byte extent
– get event list
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The exNode is Mobile Code!
(files are structured processes)
• Mappings are location-independent
• XML serialization enables interoperability
• The state of file system processes can be
captured in an abstract, portable form
• Mobile files can be freed of directory,
operating system, accounting boundaries
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Example: IBP Mail
SMTP
sender
exNode
receiver
IBP
write
IBP
read
IBP copy
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File System Services
•
•
•
•
Indirection to preserve integrity
Temporal and data extent aggregation
Reliability through RAID, replication
Performance through locality
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Active File Management
• Active Services
Time
– Active Probing to
Maintain Fault
Tolerance
– Lease Renewal
– Defragmentation
– Asynchronous Transfer
Management
allocate on
depot 1
renew on
depot 1
text
fragment to
depot 2 & 3
renew on
depot 3
Defragmentation
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Conclusions
• The Internet Backplane Protocol provides a
fabric for network state management
• Scalable and ubiquitous sharing are enabled
by weak semantics & minimal accounting
• The exNode & serialization provide a
mobile abstraction of storage aggregation
• Active file services can span OS & FS
boundaries (Log Structured Logistical FS)
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