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Dualfs

Presentation for a new File system
by

Shadow Wodash

on 20 August 2012

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Transcript of Dualfs

Dual fs File System A filesystem is a data structure! filesystem is a method of storing and organizing computer files and the data they contain to make it easy to find and access them More formally, a file system is a special-purpose database for the storage, organization, manipulation, and retrieval of data. Filesystem is an operating system service Storage
Organization
Navigation
Retrieval
Manipulation Examples Ext 2
Ext 3
JFS
Reiser FS Structure of a file system Ext 2 FS Most common File system in use

It is now becoming outdated

Its slow, and less secure Ext 3 FS Improvement over EXT 2 FS

Added Journaling Support

Better Security at the cost of performance JFS Designed for Database operations

Excellent crash recovery

Performance takes a hit as files increase Reiser FS Another FS with Journaling support

Faster with smaller files

Performance hit with time (no defragmenter) Structure of Inode Dual Duality of the disk structure! In general the filesystem has two components

Data
Meta data They behave differently, so they have to be treated differently Meta-data management Important for rash recovery

Metadata device is log structured

Only one copy of metadata is maintained

favourable in huge storage scenarios Disk layout Data device Partition for regular data

Concept of groups of data blocks

Groups are asynchronous in nature Meta-data device Contains meta information aboout the data, which includes i-nodes
Symbolic links
Super block copies Its structure is similar to a logstructured filesystem Meta-data structure Based on LFS

Partial segment is a transactional unit Structure of I-FILE Meta data device Operation Enhancing performance Meta-data prefetching

Online meta-data relocation Crash Recovery When meta-data information is consistant, then the DualFS is said to be in consistant state

Recovery is quick. quickness depends on inter-checkpoint interval

Crash recovery involves recovering the I-FILE Testing Some tests that are performed on a filesystem include Write
Re-write
Random write Read
Re-Read
Random Read Results of Testing The tool "IOZone" was used for testing Conclusion Dual fs is a new Journaling filesystem with data and meta-data managed in very different ways

Only one copy of the meta-data is maintained

Quick consistant recovery

Reduces File IO by up to 90% in some cases Prepared with prezi at prezi.com
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