Troubleshooting
Problem
Because disk sector sizes are different for virtual disks, a formula is needed to calculate the size to create the virtual disks. This document provides a formula to calculate the size of virtual disks.
Resolving The Problem
For internal disks, each page is composed of eight 520 byte sectors.
For virtual disks, each page is composed of nine 512 byte sectors. This is true of all virtual disks no matter what the backing device. Therefore, this is true for both VIOS and i hosted client partitions.
If you want a drive to be 280GB, you could use the following formula to calculate the size that the drive should be on the backing system:
( 280 * 9 ) / 8 = 315 G-Bytes.
For virtual disks, each page is composed of nine 512 byte sectors. This is true of all virtual disks no matter what the backing device. Therefore, this is true for both VIOS and i hosted client partitions.
If you want a drive to be 280GB, you could use the following formula to calculate the size that the drive should be on the backing system:
( 280 * 9 ) / 8 = 315 G-Bytes.
For 4K disk formatting, each internal disk page is composed of one 4160 byte sector.
For virtual 4K disks each page is only 4096 bytes and therefore ends up being 1/65 smaller.
In this case, to get a 280GB drive....
Use the following formula to calculate the size that the drive should be on the backing system: (280 * 65)/64 = 285
Use the following formula to calculate the size that the drive should be on the backing system: (280 * 65)/64 = 285
NOTE 1:
The above formula is not exact due to too many variables. The formula is designed to be simple to use and give a conservative estimate for the client partition.
The above formula is not exact due to too many variables. The formula is designed to be simple to use and give a conservative estimate for the client partition.
NOTE 2:
Ensure CUM PTF and PTF groups levels are at the most current levels.
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Historical Number
559489769
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Document Information
More support for:
IBM i
Component:
IBM i
Software version:
7.3.0, 7.4.0, 7.5.0
Operating system(s):
IBM i
Document number:
686571
Modified date:
17 October 2024
UID
nas8N1012304
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