Shulou(Shulou.com)06/01 Report--

Editor to share with you what features of the ZFS file system, I believe that most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to understand it!

Here are the top 10 features that ZFS proponents think ZFS has:

1. Metadata checksum ensures data integrity

Data integrity is of great importance in ZFS and is a prerequisite for many ZFS functions.

The ZFS file system uses a 256bit checksum, and when data is written to disk, the checksum is stored separately as metadata from the data associated with it. Unlike a normal block checksum, this checksum can detect misplaced writes, misread and miswrite, DMA parity errors, drive bug, unexpected excessive writes, and common physical storage decay (bit rot).

2. Copy only when you write

The ZFS file system uses a number of techniques to ensure data continuity on disk, including Copy on Write on write, that is, it is not overwritten when the data is changed-it is always written to a new block and checksum before the pointer points to the changed data. Old data may be saved and a snapshot of the file system is created during the generation of changes. File writing with ZFS is a transactional operation-either all data is written to disk or nothing is written.

3. Take advantage of Time Slider's data snapshot

The latest version of OpenSolaris shows the powerful snapshot capabilities achieved by ZFS using TimeSlider small graphics applications. You can perform regular snapshot operations on the ZFS file system through configuration settings-every 15 minutes, every hour, and so on. This snapshot takes up very little capacity and is efficient because it only holds variables from previous snapshots.

TimeSlider provides the ability to view the file system (or a home folder) and has a slider that can go back to earlier snapshot times along the timeline. When this is done, the file system or folder contents at a specific snapshot time are rendered. If you want to recover a file that was overwritten by an error, or restore the system after the upgrade failed, you just need to roll the slider back to the appropriate snapshot time.

4. Data storage pool

ZFS aggregates them into a pool of resources called zpool using available storage drives. This resource pool can use scripts, mirrors, or some kind of RAID to optimize for capacity, Imax O performance, or redundancy. If you need more storage, you just need to add more storage to zpool-- ZFS detects the newly added capacity and starts to use it automatically, balancing Icano and maximizing throughput.

5. RAIDZ and RAIDZ2

As we all know, RAID5 has a major flaw-RAID5 Write Hole. When writing data, RAID 5 is divided into two steps: first, write the data to the disk array, and then record the check code of the data on the stripe to the array. If the system is powered off when the data is just written, then the corresponding check code of the data will not have a chance to recover. If the disk fails next, the RAID rebuild process will have incorrect data. The only solution is that if the entire stripe is overwritten, a correct parity block is generated.

RAIDZ solves this problem by using a stripe of a different width, so that each write is actually a complete stripe write. Coupled with the write-only copy feature of ZFS, these completely eliminate the Write Hole defect of RAID 5. The same is true for RAIDZ2, but you can use double parity to allow two disks to be lost in the array.

Installing a RAIDZ (or RAIDZ2) array is as simple as issuing a command.

6. Solid-state disk hybrid storage pool

A storage pool can be turned into a hybrid storage pool by adding high-performance solid state disks. When these solid-state disks are used as high-performance cache disks, ZFS uses them to retain frequent access to data to improve performance. In addition, ZFS also uses L2 ARC technology to write data that does not need to be saved immediately, which will be slowly migrated to traditional, more permanent hard drives when time and resources permit.

7. Capacity

ZFS is a 128-bit file system, which means it can theoretically hold 256 trillion ZBs (1ZB = 1 billion terabytes). In practice, its capacity far exceeds what is needed, at least in the foreseeable future.

8. Data cleaning

ZFS can clean up all data in a storage pool, check each data according to the corresponding checksum to verify its integrity, detect any potential data corruption, and fix any errors that may exist.

When the data is saved redundant-in a mirror or raid array-it can repair and detect any potentially corrupted data without administrator intervention. Because data corruption is recorded, ZFS can be detected by memory modules (or other hardware) that cause the data to be improperly stored on the hard disk.

The Imap O priority for data cleaning is very low because this process has very little impact on system performance.

9. Simple and effective management

Using the ZFS command is equivalent to using a short and effective command to manage the system. For example, a 5-disk RAIDZ array can be set to use a single command:

Zpool create poolname raidz c1t0d0 c2t0d0 c3t0d0 c4t0d0 c5t0d0

10. More expectations

ZFS is still constantly updating and improving, adding new functions from time to time. ZFS's 2009 roadmap includes encryption to improve security and deduplication to improve storage efficiency.

If you are interested in trying to use ZFS, the easiest way is to download OpenSolaris or related distributions.

These are all the contents of the article "what are the functions of the ZFS file system?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.