Interstage Big DataParallel Processing ServerV1.0.0 User's Guide

D.1.2 Disk Layout

The partitions that comprise a file system in a DFS are split into three areas.

Table D.1 Three partition areas

Area type	Component used
Metadata area	MDS
Update log area
File data area	AC

Follow the procedure below to determine the disk layout.

1. Estimate the shared disk device size needed for the DFS.

   Table D.2 Shared disk device size estimation

   Area type	Estimation method
   (a) File data area	Space required for file data
   (b) Metadata area	If file data area <= 1 TB: 100 GB If file data area > 1 TB: 300 GB
   (c) Update log area	Estimation is not required because it is contained within the metadata area.
   Total	(a)+(b)

2. Determine whether the file data area will be separate from the metadata area partition.

   Separate the metadata area and file data area and allocate them to separate partitions. This separates the input-output processes to each area and can avoid contention.
   Separation of the file data area can be specified using the dataopt option of the pdfsmkfs command.

3. Determine the partitions to be used in the DFS.

   Determine the shared disk device partitions to be used in the DFS, based on the size requirement, and check the device name.
   A maximum of 256 partitions can be used.

   Point

   A DFS can be constructed with only one partition, but the input-output distribution benefits can be obtained by constructing it with multiple partitions.

4. Determine the metadata area partitions.

   Information

   If the DFS is constructed with multiple partitions, representative partitions are used as the partitions for the metadata area.