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GitHub is home to over 40 million developers working together. Join them to grow your own development teams, manage permissions, and collaborate on projects. Shell HTML 43 Solaris Porting Layer packaging for Debian and Ubuntu. Regression test suite for xfs and other filesystems. The zfs branch has been updated to be compatible with ZFS. Filebench is a file system and storage benchmark that allows to generate a high variety of workloads. Mountall enhancements for ZFS on Linux. Sun::Solaris::Kstat perl module for linux-zfs.

Dracut is a new initramfs infrastructure.

What is ZFS? Why are People Crazy About it?

Skip to content. Sign up. Pinned repositories. Type: All Select type. All Sources Forks Archived Mirrors. Select language. Shell GPL Shell 8 8 0 1 Updated Jan 16, C 2 8 2 0 Updated Nov 4, C 4 6 0 0 Updated Nov 3, Shell 15 44 1 2 Updated Aug 20, Shell 20 18 17 0 Updated Apr 20, ZFS is a combined file system and logical volume manager designed by Sun Microsystems. ZFS is scalable, and includes extensive protection against data corruptionsupport for high storage capacities, efficient data compressionintegration of the concepts of filesystem and volume managementsnapshots and copy-on-write clones, continuous integrity checking and automatic repair, RAID-Znative NFSv4 ACLsand can be very precisely configured.

The ZFS name stands for nothing—briefly assigned the backronym " Zettabyte File System ", it is no longer considered an initialism. ZFS became a standard feature of Solaris 10 in June In response, the illumos project was founded, to maintain and enhance the existing open source Solaris, and in OpenZFS was founded to coordinate the development of open source ZFS.

OpenZFS is widely used in Unix-like systems. The management of stored data generally involves two aspects: the physical volume management of one or more block storage devices such as hard drives and SD cards and their organization into logical block devices as seen by the operating system often involving a volume managerRAID controllerarray manageror suitable device driverand the management of data and files that are stored on these logical block devices a file system or other data storage.

ZFS is unusual because, unlike most other storage systems, it unifies both of these roles and acts as both the volume manager and the file system. Therefore, it has complete knowledge of both the physical disks and volumes including their condition and status, their logical arrangement into volumes, and also of all the files stored on them.

ZFS is designed to ensure subject to suitable hardware that data stored on disks cannot be lost due to physical errors or misprocessing by the hardware or operating systemor bit rot events and data corruption which may happen over time, and its complete control of the storage system is used to ensure that every step, whether related to file management or disk managementis verified, confirmed, corrected if needed, and optimized, in a way that storage controller cards and separate volume and file managers cannot achieve.

ZFS also includes a mechanism for dataset and pool-level snapshots and replicationincluding snapshot cloning which is described by the FreeBSD documentation as one of its "most powerful features", having features that "even other file systems with snapshot functionality lack". Snapshots can be rolled back "live" or previous file system states can be viewed, even on very large file systems, leading to savings in comparison to formal backup and restore processes.

A pool level snapshot known as a "checkpoint" is available which allows rollback of operations that may affect the entire pool's structure, or which add or remove entire datasets. Unlike many file systems, ZFS is intended to work towards specific aims. Its primary targets are enterprise standard data management and commercial environments, with hardware capable of supporting ZFS' capabilities for data resilience and the resources needed to serve data efficiently.

Because ZFS acts as both volume manager and file systemthe terminology and layout of ZFS storage covers two aspects:. ZFS commands allow examination of the physical storage in terms of devices, vdevs they are organized into, data pools stored across those vdevs, and in various other ways. They can be conceived as groups of disks that each provide redundancy against failure of their physical devices. Each vdev must be able to maintain the integrity of the data it holds, and must contain enough disks that the risk of data loss within it, is acceptably tiny.

If any vdev were to become unreadable due to disk errors or otherwise then the entire pool it is part of, will also fail. See data recovery below. Each vdev acts as an independent unit of redundant storage. Devices might not be in a vdev if they are unused spare disks, disks formatted with non-ZFS filing systems, offline disks, or cache devices. The physical structure of a pool is defined by configuring as many vdevs of any type, and adding them to the pool. ZFS exposes and manages the individual disks within the system, as well as the vdevs, pools, datasets and volumes into which they are organized.

Within any pool, data is automatically distributed by ZFS across all vdevs making up the pool.


ZFS stripes the data in a pool across all the vdevs in that pool, for speed and efficiency. Each vdev that the user defines, is completely independent from every other vdev, so different types of vdev can be mixed arbitrarily in a single ZFS system.

If data redundancy is required so that data is protected against physical device failurethen this is ensured by the user when they organize devices into vdevs, either by using a mirrored vdev or a RaidZ vdev. Data on a single device vdev may be lost if the device develops a fault. Data on a mirrored or RaidZ vdev will only be lost if enough disks fail at the same time or before the system has resilvered any replacements due to recent disk failures.

A ZFS vdev will continue to function in service if it is capable of providing at least one copy of the data stored on it, although it may become slower due to error fixing and resilvering, as part of its self-repair and data integrity processes. However, ZFS is designed to not become unreasonably slow due to self-repair unless directed to do so by an administrator since one of its goals is to be capable of uninterrupted continual use even during self checking and self repair.

Since ZFS device redundancy is at vdev level, this also means that if a pool is stored across several vdevs, and one of these vdevs completely fails, then the entire pool content will be lost. This is similar to other RAID and redundancy systems, which require the data to be stored or capable of reconstruction from enough other devices to ensure data is unlikely to be lost due to physical devices failing.

Therefore, it is intended that vdevs should be made of either mirrored devices or a RaidZ array of devices, with sufficient redundancy, for important data, so that ZFS can automatically limit and where possible avoid data loss if a device fails.Joinsubscribers and get a daily digest of news, geek trivia, and our feature articles.

ZFS is commonly used by data hoarders, NAS lovers, and other geeks who prefer to put their trust in a redundant storage system of their own rather than the cloud. The Z file system is a free and open source logical volume manager built by Sun Microsystems for use in their Solaris operating system.

Some of its most appealing features include:. No matter how much hard drive space you have, ZFS will be suitable for managing it. Everything you do inside of ZFS uses a checksum to ensure file integrity. You can rest assured that your files and their redundant copies will not encounter silent data corruption. Also, while ZFS is busy quietly checking your data for integrity, it will do automatic repairs anytime it can.

zFS (z/OS file system)

Here are the commands for installing ZFS on some of the most popular Linux distributions. If you have some other distribution, check out zfsonlinux. You should get an output like this:.

If you want to see which three disks you selected for your pool, you can run sudo zpool status :. Then when we go to read the 3 KB file, each hard drive would present 1 KB to us, combining the speed of the three drives.


This makes writing and reading data fast, but also means we have a single point of failure. If just one hard drive fails, we will lose our 3 KB file. Bam, our zpool is gone. If a single disk in your pool dies, simply replace that disk and ZFS will automatically rebuild the data based on parity information from the other disks. To lose all of the information in your storage pool, two disks would have to die. To accomplish this, we can use the same zpool create command as before but specify raidz after the name of the pool:.

As you can see, df -h shows that our 9 TB pool has now been reduced to 6 TB, since 3 TB is being used to hold parity information. With the zpool status command, we see that our pool is mostly the same as before, but is using RAID-Z now.

Check back with us for future articles about ZFS, see the man pages, and search around for the endless niche guides and Youtube videos covering ZFS functions. The Best Tech Newsletter Anywhere. Joinsubscribers and get a daily digest of news, comics, trivia, reviews, and more.

Windows Mac iPhone Android.A Solaris file system that uses storage pools to manage physical storage. The ZFS pooled storage model eliminates the concept of volumes and the associated problems of partitions, provisioning and stranded storage by enabling thousands of file systems to draw from a common storage pool, using only as much space as it actually needs.

Over time, ZFS gained a lot more features besides bit capacity, such as rock-solid data integrity, easy administration, and a simplified model for managing your data. Stay up to date on the latest developments in Internet terminology with a free newsletter from Webopedia. Join to subscribe now. From A3 to ZZZ we list 1, text message and online chat abbreviations to help you translate and understand today's texting lingo. Includes Top Have you heard about a computer certification program but can't figure out if it's right for you?

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Файловая система ZFS: Часть 1. Отказоустойчивость

Data Storage. IT Management. What is your company size? What is your job title? What is your job function? Searching our resource database to find your matches Computer Architecture Study Guide Computer architecture provides an introduction to system design basics for most computer science students. Browse Technology Definitions:. Acceptable Use Policy.Its development started in and it was officially announced in In it was integrated into the main trunk of Solaris and released as part of OpenSolaris.

Currently it can store up to ZiB zebibytes. The kernel module is provided by default. Rationale Ubuntu server, and Linux servers in general compete with other Unixes and Microsoft Windows. ZFS is a killer-app for Solaris, as it allows straightforward administration of a pool of disks, while giving intelligent performance and data integrity.

The available disks of any size are used to the best of their ability. Compression can be used to increase bandwidth. Reiser 4, and cloop?

ZFS is bit, meaning it is very scalable. With ZFS, this time is cut in half. Parity calculations make this a fairly slow set-up because of the number of writes of small files. She upgrades to ZFS and sees performance benefits, because small files are mirrored instead of included in parity calculations. Manuel has a mirrored disk array. Fluctuations in his computer's PSU are causing silent data corruption errors. ZFS detects the errors and reports back those errors to Manuel, protecting the data already on disk from further corruption.

Andreas has a disk that has suffered a partial failure. Since he chose a policy of two copies for his personal file system volume, he may be able to recover some of his latest personal data without having to resort to tape backups.

One of the disks experiences a catastrophic disk motor failure. ZFS automatically reconstructs the data on that disk with zero downtime and minimal data transfer or performance impact to the array. ZFS last edited by seth-arnold. Partners Support Community Ubuntu.The Z File Systemor ZFSis an advanced file system designed to overcome many of the major problems found in previous designs.

Data integrity: All data includes a checksum of the data. When data is written, the checksum is calculated and written along with it. When that data is later read back, the checksum is calculated again.


If the checksums do not match, a data error has been detected. ZFS will attempt to automatically correct errors when data redundancy is available. Pooled storage: physical storage devices are added to a pool, and storage space is allocated from that shared pool. Space is available to all file systems, and can be increased by adding new storage devices to the pool. Performance: multiple caching mechanisms provide increased performance. ARC is an advanced memory-based read cache.

ZFS is significantly different from any previous file system because it is more than just a file system. Combining the traditionally separate roles of volume manager and file system provides ZFS with unique advantages. The file system is now aware of the underlying structure of the disks. Traditional file systems could only be created on a single disk at a time. If there were two disks then two separate file systems would have to be created.

In a traditional hardware RAID configuration, this problem was avoided by presenting the operating system with a single logical disk made up of the space provided by a number of physical disks, on top of which the operating system placed a file system. ZFS 's combination of the volume manager and the file system solves this and allows the creation of many file systems all sharing a pool of available storage.

One of the biggest advantages to ZFS 's awareness of the physical layout of the disks is that existing file systems can be grown automatically when additional disks are added to the pool.

This new space is then made available to all of the file systems. ZFS also has a number of different properties that can be applied to each file system, giving many advantages to creating a number of different file systems and datasets rather than a single monolithic file system.

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