Network Attached Storage For Database Applications And The Impact Of DAIS.Filers are becoming an increasingly popular storage solution for database applications. This trend has been driven primarily by a greatly reduced total cost of ownership (TCO (1) (Total Cost of Ownership) The cost of using a computer. It includes the cost of the hardware, software and upgrades as well as the cost of the inhouse staff and/or consultants that provide training and technical support. See ROI. ) when compared to direct-attached or SAN-attached storage. The Direct Access File System (DAFS (Direct Access File System) A high-performance file sharing protocol based on the VI memory-to-memory architecture. Designed for storage area networks (SANs), DAFS provides bulk data transfer directly between the application buffers of two machines without ) protocol promises to further accelerate this trend by adding high performance and transport independence to the TCO advantage.
Traditionally, database servers have been large complex systems configured with large amounts of memory and disk storage.
To improve the reliability and availability of these database servers, add-ons implementing some form of RAID protection have in recent years been utilized. Some of these solutions use mirroring (RAID 1), while others use parity protection (RAID 3, 4 or 5); some use hardware support, and some use special software.
However, these solutions have some shortcomings A shortcoming is a character flaw.
Shortcomings may also be:
in full central processing unit
Principal component of a digital computer, composed of a control unit, an instruction-decoding unit, and an arithmetic-logic unit. cycles (reducing the CPU cycles available for database processing). Even if hardware RAID is used, CPU cycles are still required to manage the file system on which the database datafiles are placed (datafiles being those physical disk files in which a database stores data).
Database applications themselves are a software category in their own right due to their very I/O-intensive nature. Rather than simply relying on the features and capabilities of the underlying operating system operating system (OS)
Software that controls the operation of a computer, directs the input and output of data, keeps track of files, and controls the processing of computer programs. to provide performance, scalability, and management, database engines have traditionally tried to manage hardware resources directly.
For example, many database installations are configured so that the database software writes directly to a "raw" device, in order to bypass the operating system's file system buffering. In most cases this results in better performance, but it also has two significant shortcomings. First, when additional disk space is required for the database operation, the steps required to increase the size of the raw disk partition See partition. are complex and time-consuming. Second, the file management tools available with the operating system for checking consistency, performing backups, etc., are not available when raw disk I/O (Input/Output) The transfer of data between the CPU and a peripheral device. Every transfer is an output from one device and an input to another. See PC input/output.
I/O - Input/Output is utilized.
In recent years, however, operating system file management has improved to such a degree that the performance advantage provided by raw I/O often no longer outweighs the administrative disadvantages, and more and more database vendors have switched to recommending the use of a file system.
A more recent development, for example, has been the use of Network Appliance's Filers, to store database datafiles, instead of directattached or SAN-attached storage arrays (See Figure).
A Filer is a high-performance high-integrity file storage appliance, which is connected to the database server using Ethernet, and uses a standard network protocol to move database information to and from the database server. As the word "appliance" implies, a Filer is a special-purpose computer A computer designed from scratch to perform a specific function. Contrast with general-purpose computer. designed specifically to optimize file transfer and storage while offering plug-and-play ease of use.
Filers feature integrated RAID protection, a highly optimized file system, and extensive file management capabilities, thereby reducing the complexity of the database server, which no longer has to mirror critical data files or manage a large complex file system.
Filer Advantages For Database Applications
The use of Filers to store database datafiles offers some significant advantages over the alternate approach of directattached storage or SAN-attached storage, including excellent performance, greatly improved ease of administration, and significantly reduced total cost of ownership.
Database administrators (DBAs) today spend their time on a wide range of tasks. With talent in short supply, maximizing the use of IT staff time is an important factor in operating the database, and directly relates to ownership costs.
The use of a Filer for database storage can significantly reduce the routine administrative burden on DBAs. The task of managing disk space and reliability features is kept extremely simple. Backup activities are greatly simplified, and require less downtime The time during which a computer is not functioning due to hardware, operating system or application program failure. . And spending time "Spending Time" is the first single released by Christian artist Stellar Kart.
The lyrics describe the band members desire to spend "more time with God". "Sometimes it’s a real struggle to spend time with God. and effort to architect the correct distribution of data files across separate disks is no longer required. This frees up time for them to focus on more valueadded tasks, such as database design and performance tuning Performance tuning is the improvement of system performance. This is typically a computer application, but the same methods can be applied to economic markets, bureaucracies or other complex systems. . A recent report by The Input Group, entitled "Database Storage Solutions", found that with Network Appliance (1) A specialized device for use on a network. For example, Web servers, cache servers and file servers can be implemented as general-purpose computers with the appropriate software or as network appliances, which are computers dedicated to a single function and cannot do anything Filers, DBAs spend nearly 90% of their time on value-added tasks, compared with only 60% for the leading SAN-attached storage.
Filers greatly simplify the ability to scale up disk space. Since a Filer provides one large file system, it is simply a matter of adding a new disk drive to the storage array, issuing a couple of simple commands, and waiting long enough for the filer to zero out the new disk drive. Database files can now be either manually extended or allowed to automatically extend into the new space. The Input report found that SAN-attached storage typically takes four hours to scale up by 200GB, compared with less than 10 minutes for NetApp Filers.
Filers have a unique capability known as Snapshots where the current state of the file system is preserved for a specified interval, or until deliberately terminated. Snapshots provide a read-only view that can be used as checkpoints (to recover accidentally deleted files), or for making backups. Combining Snapshots with the online backup Using the Web to store copies of data for backup. There are numerous providers on the Internet that charge for storage, and fees are typically based on capacity. Online backup services provide offsite backup, which is essential for disaster recovery. See backup types. functionality provided in most databases, Filers can maximize the availability of the database even during backup procedures. Consequently, routine backup and recovery tasks, which typically consume 35% of a DBA's time with SAN-attached storage, take only 10% for Filer environments.
Total Cost Of Ownership Advantage
The Input report on "Database Storage Solutions" concluded with a Total Cost of Ownership calculation, taking account of:
* Product cost for the underlying hardware and database tools, including maintenance costs and upgrade costs;
* Database implementation costs, including training costs;
* Operation costs (including support and helpdesk); and
* Cost of planned and unplanned downtime.
They found the annual total cost of ownership per Gigabyte for database environments is 75% lower for NetApp Filers than for competing SAN-attached storage.
DAFS And Database Applications
The Direct Access File System (DAFS) protocol promises to deliver the TCO advantages demonstrated by Network Appliance Filers to SAN and machine room environments, with significant database performance enhancements. DAFS is transport-agnostic and will run on Ethernet, Fibre Channel, or InfiniBand and fabrics.
DAFS is a file access protocol based on NFS (Network File System) The file sharing protocol in a Unix network. This de facto Unix standard, which is widely known as a "distributed file system," was developed by Sun. See file sharing protocol and WebNFS.
NFS - Network File System , which is being specifically designed to take advantage of the "Direct" (RDMA (Remote Direct Memory Access) A communications protocol that provides transmission of data from the memory of one computer to the memory of another without involving the CPU. InfiniBand, Virtual Interface (VI) and RDMA Over IP are all forms of RDMA. ) and asynchronous I/O Overlapping input and output with processing. Both the hardware and the software must be designed for this capability. The peripherals must be able to run independent of the CPU, and the software must be designed to manage it. features of standard memory-to-memory interconnects such as VI and InfiniBand. This translates to wire-speed transfers over gigabit and 10 gigabit networks, combined with a significant reduction in the client-side overhead. When the "client" is a database server, this means a significant increase in the percentage of CPU cycles available for processing database operations.
DAFS gives applications direct access to transport resources, bypassing the OS, and enabling them to optimally manage their own I/O. This model is an extremely good fit for I/O-intensive applications such as database engines. And in fact, the leading database vendors have been very active in the development of the DAFS protocol spec to ensure that it provides the features that will enable them to realize significant database performance gains.
DAFS can be implemented in a number of different ways. Kernel implementations can provide transparent access to DAFS by intercepting standard file I/O Input/Output operations such as open, close, read, write and append, all of which deal with standard disk or tape files. The term would be used to refer to regular file operations in contrast to low-level system I/O such as dealing with virtual memory pages or OS tables of contents. calls or device I/O calls. User-space DAFS library implementations can provide optimal performance by providing an API (Application Programming Interface) A language and message format used by an application program to communicate with the operating system or some other control program such as a database management system (DBMS) or communications protocol. which enables applications to directly manage I/O. Again the leading database vendors are active within the DAFS Collaborative helping to ensure that the DAFS API Specification includes the features they need.
The DAFS Collaborative
The DAFS Collaborative was formed in June 2000 by Network Appliance, Intel, and other leading systems and storage networking vendors, with the goal of making the Direct Access File System protocol available to the industry. Today more than 70 companies are contributing to the development of the DAFS Protocol Specification and the DAFS API Specification. The group is soliciting industry review and feedback before submitting the Specifications to the appropriate standards bodies Following are some of the standards bodies defined in this database. For Windows users of CDE, look up Lessons/Review/Associations. For Web users of CDE's online HTML version, review the Lessons list at the bottom of the definition.
Organization Covers ANSI U.S. .
Additional participants are welcome and can join online. For more information, contact Werner Glinka, executive director of the DAFS Collaborative, at: Werner.firstname.lastname@example.org.
David Dale This article is about David Dale. For other uses, see David Dale (author).
David Dale (1739 – 1806) was a Scottish merchant and businessman, famous for establishing the influential weaving community of New Lanark. is an industry evangelist evangelist (ĭvăn`jəlĭst) [Gr.,=Gospel], title given to saints Matthew, Mark, Luke, and John. The four evangelists are often symbolized respectively by a man, a lion, an ox, and an eagle, on the basis of Rev. 4.6–10. at Network Appliance (Waltham, MA) and a co-chair of the DAFS Collaborative.