ext3cow
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Developer(s) | (ext3cow versioning), Stephen Tweedie (ext3 design and implementation), Rémy Card (original ext2 design and implementation), Theodore Ts'o (tools and improvements), (xattrs and ACLs), (online resizing), et al. |
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Full name | Third extended file system with copy-on-write |
Introduced | July 2003Linux | with
Partition identifier | 0x83 (MBR) EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 (GPT) |
Structures | |
Directory contents | Table, Tree |
File allocation | bitmap (free space), table (metadata) |
Bad blocks | Table |
Limits | |
Max. volume size | 8TiB |
Max. file size | 2TiB |
Max. number of files | Variable1 |
Max. filename length | 255 bytes |
Allowed characters in filenames | All bytes except NUL, '/' and '@' |
Features | |
Dates recorded | modification (mtime), attribute modification (ctime), access (atime) |
Date range | December 14, 1901 - January 18, 2038 |
Date resolution | 1s |
Forks | Yes |
Attributes | No-atime, append-only, synchronous-write, no-dump, h-tree (directory), immutable, journal, secure-delete, top (directory), allow-undelete |
File system permissions | Unix permissions, ACLs and arbitrary security attributes (Linux 2.6 and later) |
Transparent compression | No |
Transparent encryption | No (provided at the block device level) |
Other | |
Supported operating systems | Linux |
Ext3cow or third extended filesystem with copy-on-write is an open source, versioning file system based on the ext3 file system. Versioning is implemented through block-level copy-on-write. It shares many of its performance characteristics with ext3.
Ext3cow provides a time-shifting interface that permits a real-time and continuous view of data in the past. Time-shifting is a novel interface, introduced in ext3cow, allowing users to navigate through and access past namespaces by adding a time component to their commands.
Ext3cow was designed to be a platform for compliance with the versioning and auditability requirements of recent US electronic record retention legislation, such as Sarbanes-Oxley and HIPAA.
A version of ext3cow for the Linux 2.6 kernel was released on March 30, 2007.
Details on ext3cow's implementation can be found in a 2005 paper.[1]
See also[]
References[]
- ^ Zachary Peterson and Randal Burns (May 2005). "Ext3cow: A Time-Shifting File System for Regulatory Compliance" (PDF). ACM Transactions on Storage, 1(2). Archived from the original (PDF) on 2011-07-19. Retrieved 2009-02-03.
External links[]
- https://web.archive.org/web/20060820153522/http://www.ext3cow.com/ ext3cow homepage (domain expired)
- "ext3cow". Freecode.
- Disk file systems
- File systems supported by the Linux kernel