Table of Contents
What is extent based allocation?
Disk space is allocated in 512-byte sectors to form logical blocks. VxFS supports logical block sizes of 1024, 2048, 4096, and 8192 bytes. The default block size is 1K for file system sizes of up to 1 TB, and 8K for file system sizes 1 TB or larger.
What is an extent in storage?
In computing, an extent is a contiguous area of storage reserved for a file in a file system, represented as a range of block numbers, or tracks on count key data devices. A file can consist of zero or more extents; one file fragment requires one extent.
What is an extent in mainframe?
An extent is a contiguous number of disk drive tracks, cylinders, or blocks. Data sets can increase in extents as they grow. Older types of data sets can have up to 16 extents per volume. Newer types of data sets can have up to 128 extents per volume or 255 extents total on multiple volumes.
What is the size of an extent?
An extent is a block of storage within a table space container. It represents the number of pages of data that will be written to a container before writing to the next container. When you create a table space, you can choose the extent size based on your requirements for performance and storage management.
What is an extent in a data set?
An extent is a logical unit of database storage space allocation made up of a number of contiguous data blocks. One or more extents in turn make up a segment. When the existing space in a segment is completely used, Oracle allocates a new extent for the segment.
How is space allocation calculated in JCL?
Determine the actual BLKSIZE you will use.
- Determine the blocking factor (number of logical records in 1 physical record) you will use. This is usually considered optimal – 23476/record length. For 80 byte records, 23476 / 80 = 293.
- Determine the BLKSIZE – 293 * 80 = 23440.
How do I allocate a large dataset in mainframe?
To allocate a large format data set, specify LARGE for the DSNTYPE value on the JCL DD statement, the access method services ALLOCATE command, the TSO/E ALLOCATE command, or SVC 99 (dynamic allocation).
What is extent in SQL?
An extent is eight physically contiguous pages, or 64 KB. This means SQL Server databases have 16 extents per megabyte. SQL Server has two types of extents: Uniform extents are owned by a single object; all eight pages in the extent can only be used by the owning object. Mixed extents are shared by up to eight objects.
What is the purpose for setting the processing extent environment variable?
The Extent environment defines the features or rasters that will be processed by a tool. It is useful when you need to process only a portion of a larger dataset. You can think of this setting as a rectangle used to select input features and rasters for processing.
What is extent in mainframe?
What is processing extent in GIS?
Processing extent can be used to define the geographic area of interest to be applied to a geoprocessing tool. The extent is defined as a rectangle with minimum and maximum x (longitude) and y (latitude) coordinates.
What does spatial extent mean in geography?
The spatial extent of a raster, represents the “X, Y” coordinates of the corners of the raster in geographic space. This information, in addition to the cell size or spatial resolution, tells the program how to place or render each pixel in 2 dimensional space.
What is primary and secondary allocation in JCL?
When the primary allocation of space is filled, space is allocated in secondary storage amounts (if a secondary amount was specified) until the volume is full. The extents can then continue in this manner to another volume until the additional volumes are exhausted. Extents for a striped data set are handled by stripe.
What is the extent size of India?
It is the seventh-largest country in the world, with a total area of 3,287,263 square kilometres (1,269,219 sq mi). India measures 3,214 km (1,997 mi) from north to south and 2,933 km (1,822 mi) from east to west.
What is extent in VxFS?
In simple terms, an extent is a contiguous area of storage in a file system, reserved for a file. Veritas File System (VxFS) makes it possible to pre-allocate space to a file at the time of the request rather than when data is written into the file. When starting to write to a file, a whole extent is allocated.
What determines the size of the VxFS intent log?
The VxFS intent log is allocated when the file system is first created and the size is determined by the size of the file system. The larger the file system, the larger the intent log.
How do I perform a VxFS intent log replay?
The mount command automatically runs the VxFS fsck command to perform an intent log replay if the mount command detects a dirty log in the file system. The VxFS intent log is allocated when the file system is first created and the size is determined by the size of the file system. The larger the file system, the larger the intent log.
What is the VxFS fsck command?
The mount command automatically runs the VxFS fsck command to perform an intent log replay if the mount command detects a dirty log in the file system. The VxFS intent log is allocated when the file system is first created and the size is determined by the size of the file system.