ZFS

Description

ZFS for Z Spins System , is a filing system open source under license CDDL. “Z” does not mean anything in particular officially but is known in the press under various names such Zettabyte of the English unit zettabyte (Zettaoctet in French) concerning data processing data storage, but also ZFS for the last word in the filesystems ( the last Word in filesystems ).

Produced by Sun Microsystems for Solaris 10 and superior, it was conceived by the team of Jeff Bonwick. Announced for September 2004, it was integrated into Solaris on October 31st, 2005 and on November 16th, 2005 as a feature of the build 27 of OpenSolaris. Sun announced that ZFS was integrated in the update of Solaris gone back to June 2006, that is to say one year after the opening of the OpenSolaris community.

The characteristics of this filing system are its very high storage capacity, the integration of all the preceding concepts concerning the filesystems and management of volume in only one product . It integrates the structure One-Disk, it is light and easily allows the installation of a platform of management of storage.

Features

Theoretical capacity

ZFS is a filesystem 128 bits, which means that it can provide 16 billion billion times what provide the filesystems 64 bits current. The limitations of ZFS are so broad that there will be never practical operations which can reach them. , “To fill a filing system 128 bits would exceed the quantum limits of data storage. You could not fill a space of data 128 bits without making boil the oceans. ”.

Some of the limits of ZFS:

• 2⁴⁸: the number of possible images (snapshot);
• 2⁴⁸: the number of files in each filesystem;
• 16 Exa - bytes: maximum size of the filesystem;
• 16 exa-bytes: maximum size of only one file;
• 2⁵⁶: the theoretical maximum number of files per repertory (actually limited to 2⁴⁸ by the maximum number of files in a filesystem).

For example, if a user created 1000 files a second, it would take 90 centuries to arrive at the limit of files.

In answer to a question concerning the relationship between filling a filing system ZFS and boiling of the oceans, Bonwick answered:

Although we would like all that the Loi of Moore continues to apply for always, the quantum Mécanique imposes some fundamental limits on the computing speeds and storage capacities of any physical object. In particular, it was shown that a Kilogram of matter contained in a volume of a Liter could carry out to the maximum 10⁵¹ operations per seconds on to the maximum 10³¹ bits of information. A storage space 128 bits entirely filled would contain 2¹²⁸ blocks = 2¹³⁷ bytes = 2¹⁴⁰ bits; from where the mass minimum necessary to contain the bits would be of (2¹⁴⁰ bits)/(10³¹ bits/kg) = 138 billion kg.

However, to be able to function with this limit of 10³¹ bits/kg, the totality of the mass of the computer should be made up of pure energy. According to E=mc², energy at rest of a billion kg is of 1,2×10²⁸ Joules. The mass of the oceans is of approximately 1,4×10²¹ kg. One needs approximately 4000 J to raise the temperature of one kg water of a Degree Celsius, that is to say: 400,000  J to heat cold state with boiling. The latent heat of vaporization adds 2 more J/kg million. Thus energy necessary to carry to boiling the oceans is of approximately (2,4×10⁶ J/kg) × (1,4×10²¹ kg) = 3,4×10²⁷ J. Thus, to entirely fill a storage space 128 bits would consume, literally, more energy than to make boil the oceans.

Platform

ZFS is integrated on Solaris SPARC and Solaris x86, the data can be exchanged between two architectures. Moreover, the complex operation of data makes it possible to store information in a compatible way between the systems Big-Endian and Little-Endian, an advantage concerning the manner of storing the data before, so constraining. Each block of data is written in the native order of the system writing the data: during the reading if Big-Endian does not function the data are transformed into memory then written in the corresponding system.

There exists a port for Fuse/Linux which is with the state of beta. Parted magic, a distribution LiveCD proposes nevertheless its support. Currently, there is no project for HP-UX, or even AIX. But since ZFS is in open source, the bearing can be carried out without the participation of Sun. Matt Dillon of the project DragonFlyBSD right now envisaged to carry ZFS for version 1.5 of her OS.

The system Mac OS X 10.5 Leopard of Apple currently makes it possible to read in reading only the contents of a partition ZFS.

ZFS is also supported recently on FreeBSD, the bearing is almost finished, partitions ZFS can beings assembled, dismounted, read and written. Only lack the support of the ACL which will be implemented from here at a few weeks.

To reach a partition ZFS since Windows, it is possible to download and install SFU and to share the partition via NFS (Unix Services for Windows).

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