Solaris ZFS is designed from the ground up to meet the increasingly sophisticated needs of a general-purpose file system, from the desktop to the datacenter. Anyone who has ever lost important files, run out of space on a partition, spent weekends adding new storage to servers, tried to grow or shrink a file system, or experienced data corruption knows that there is lots of room for improvement to file systems and volume managers.

Highlights

• Mind-boggling scalability—128-bit file system, providing 16 billion times the capacity of a 64-bit file system
• Rock-solid data integrity—all data is protected by 256-bit checksums, consistency of data is maintained at all times
• Breathtaking speed—longstanding and cutting-edge technologies combine for optimized performance
• Unprecedented manageability—eliminates the need for a volume manager, GUI automates administrator intent
• POSIX compliant—applications run without modification

The Future-proof File System

Solaris ZFS offers a dramatic advance in data management with an innovative approach to data integrity, tremendous performance improvements, and a welcome integration of file system and volume management capabilities. The centerpiece of this new architecture is the concept of the virtual storage pool which de-couples the file system from physical storage in the same way that virtual memory abstracts the address space from physical memory; allowing for much more efficient use of the storage devices. In ZFS, space is shared dynamically between multiple file systems from a single storage pool, and is parceled out from the pool as file systems request it. So, physical storage can be added to or removed from storage pools dynamically, without interrupting services. This provides new levels of flexibility, availability, and performance. And in terms of scalability, Solaris ZFS is a 128-bit file system. Its theoretical limits are truly mind-boggling—2¹²⁸ bytes of storage and 2⁶⁴ for everything else, such as file systems, snapshots, directory entries, and devices.

Cutting-Edge Data Integrity

Solaris ZFS combines proven and cutting edge technologies like copy-on-write and end-to-end 256-bit checksumming to ensure that the data on the disk is self-consistent at all times. With ZFS, data is always written to a new block on disk before changing the pointers to the data and committing the write. And, because the file system is always consistent, time-consuming recovery procedures like fsck are not required if the system is shut down in an unclean manner. Copy-on-write also lets administrators to take consistent backups or roll data back to a known point in time.

The Solaris 10 OS with Solaris ZFS is the only known OS designed to provide end-to-end 256-bit checksumming for all data. Solaris ZFS constantly reads and checks data to help ensure it is correct, and if it detects an error in a mirrored pool, the technology can automatically repair the corrupt data. This relentless vigilance on behalf of availability protects against costly and time-consuming data loss (even previously undetectable silent data corruption).

Near platter speeds

This radical new architecture optimizes and simplifies the code paths from the application to the hardware, producing sustained throughput at near platter speeds. New block allocation algorithms accelerate write operations, and consolidate what would traditionally be many small random writes into a single more efficient sequential operation. Additionally, ZFS implements "intelligent prefetch", performing read ahead (in either direction) for sequential data streaming, and can adapt its read behavior on-the-fly for more complex access patterns.

ZFS also eliminates bottlenecks and increases the speed of both reads and writes by striping data across all the available storage devices, balancing IO and maximizing throughput. And, as you add disks to the storage pool, ZFS immediately begins to allocate blocks from those devices, increasing your effective bandwidth as each device is added. So, system administrators no longer need to be preoccupied monitoring their storage devices to see if any of them are causing IO bottlenecks.

Simplified Administration

Most file system administration tasks are painful and slow operations that are relatively uncommon. Because these types of tasks are so infrequently performed, they are more prone to errors that can destroy a great amount of data very quickly. Solaris ZFS helps alleviate this problem by automating both common and less frequent administrative tasks.

Administering storage with Solaris ZFS is extremely easy because the design lets administrators state the intent of their storage policies rather than all of the details needed to implement them. Creating a file system or performing other administrative activities in ZFS is very fast (under 1 second regardless of the size). There is no need to configure (or worse, reconfigure) the underlying storage devices or volumes as this is handled automatically when they are added to a pool. ZFS also allows a system administrator to guarantee a minimum capacity for a file system or to set quotas to limit the maximum size.

Volume Management is a Thing of the Past

Unlike traditional file systems that require a separate volume manager, the ZFS architecture introduces the integration of volume management functions. In the traditional file system/volume manager combination there is a 1 to 1 mapping between the file system and its associated volume. ZFS breaks out of this limitation with its use of the storage pool model. When capacity is no longer required it by one file system in the pool, it becomes available to others. So system administrators can now create a file system for each individual user on a system without having to create and manage volumes to manage capacity.

Reduced Costs

Solaris ZFS can reduce costs by decreasing the time and complexity of administrative tasks, efficiently using resources, and eliminating volume manager licensing. All administration tasks are performed online, resulting in zero downtime for administration. In addition, the technology does not require a separate support contract because it is part of the Solaris OS. This can greatly simplify support issues; there is a single point of contact and only a single maintenance contract for all software layers between the application and storage resources.

Compatibility

ZFS is fully POSIX compatible and applications will not need any changes or modifications to use ZFS and take advantage of its industry leading capabilities. Existing storage infrastructure—device drivers, storage fabric, and devices–works without change as well. For applications that prefer to operate directly on block devices ZFS provides a volume emulator (Zvol) that provides all of the benefits of transactional integrity and checksums and is still compatible with existing volume manager block-based interfaces.

Conclusion

With data security and integrity, virtually unlimited scalability, and easy and automated manageability, Sun once again leads with Solaris ZFS, simplifying storage and data management for demanding applications today, and well into the future.

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