World Library  
Flag as Inappropriate
Email this Article

One File System

Article Id: WHEBN0027697608
Reproduction Date:

Title: One File System  
Author: World Heritage Encyclopedia
Language: English
Subject: List of file systems
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

One File System

OneFS
Developer Isilon Systems
Full name OneFS
Introduced 2003 (OneFS 1.0 -- based on FreeBSD)
Structures
Directory contents B+ trees
File allocation B+ trees
Limits
Max. file size 4TB
Max. number of files Cluster size dependent
Max. filename length 255 bytes
Max. volume size 15PB+ (143+ nodes at 108TB each);[1] 65535 nodes theoretical limit
Allowed characters in filenames All bytes except NUL and '/'
Features
Dates recorded Create time, rename time, mtime, ctime, atime
Forks Yes (extended attributes and Alternate Data Streams)
File system permissions Yes (Unix permissions and NTFS ACLs)
Transparent compression No
Transparent encryption No
Supported operating systems OneFS

The OneFS file system is a parallel distributed networked file system designed by Isilon Systems for use in its Isilon IQ storage appliances. OneFS is a FreeBSD variant and utilizes zsh as its shell. OneFS has its own specialized command set,[2] all of which start with "isi", which is used to administer the system.

On-disk Structure

All data structures in the OneFS file system maintain their own protection information. This means in the same filesystem, one file may be protected at +1 (basic parity protection) while another may be protected at +4 (resilient to four failures) while yet another file may be protected at 2x (mirroring); this feature is referred to as FlexProtect.[3] FlexProtect is also responsible for automatically rebuilding the data in the event of a failure. The protection levels available are based on the number of nodes in the cluster and follow the Reed Solomon Algorithm. Blocks for an individual file are spread across the nodes; for example, block 0 may be on Node 3, block 1 on Node 1, and the related parity block on Node 5. This allows entire nodes to fail without losing access to any data. File metadata, directories, snapshot structures, quotas structures, and a logical inode mapping structure are all based on mirrored B+ trees. Block addresses are generalized 64-bit pointers that reference (node, drive, blknum) tuples. The native block size is 8192 bytes; inodes are 512 bytes on disk.

One distinctive characteristic of OneFS is that metadata is spread throughout the nodes in a homogeneous fashion. There are no dedicated metadata servers. The only piece of metadata that is replicated on every node is the address list of root btree blocks of the inode mapping structure. Everything else can be found from that starting point, following the generalized 64-bit pointers.

Clustering

Nodes running OneFS must be connected together with a high performance, low-latency back-end network for optimal performance. OneFS 1.0-3.0 used Gigabit Ethernet as that back-end network. Starting with OneFS 3.5, Isilon offered Infiniband models. Now all nodes sold utilize an Infiniband back-end.

Data, metadata, locking, transaction, group management, allocation, and event traffic go over the back-end RPC system. All data and metadata transfers are zero-copy. All modification operations to on-disk structures are transactional and journaled.

Protocols

OneFS is equipped with options for accessing storage via NFS, CIFS/SMB, FTP, HTTP, iSCSI, and HDFS. It can utilize non-local authentication such as Active Directory, LDAP, and NIS. It is also capable of interfacing with backup devices using NDMP.

Versions

  • 1.0, 2.0, 3.0, 4.0
  • 4.1, 4.5, 4.6
  • 4.7
    • 4.7.1 to .11
  • 5.0
    • 5.0.0 to .8
  • 5.5 (based on FreeBSD 6.1)[4][5]
    • 5.5.1 to .2
    • 5.5.3 - OS updates with rolling reboots of individual nodes.
    • 5.5.4 - Adds iSCSI
    • 5.5.5 to .7
  • 6.0 - Up to 10.4 PB in a single file system
    • 6.0.1 to .4
  • 6.5(based on FreeBSD 7.3)[4]
    • 6.5.1 to .5
  • 7.0 - released November 2012;[6] (based on FreeBSD 7.4-STABLE)[4]
    • 7.0.1 to .2
  • 7.1 - released October 2013[7]

See also

References

External links

  • Isilon Web page


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.