KERNSAFE - iSCSI SAN Software and Storage Virtualization

Construct Partition Table

"How to Use “Construct Partition Table” in Partition-to-Disk iSCSI Devices"

When creating an iSCSI target based on a partition, the following options are available:

• Persistent Exclusive Access on This Device
• Hold and Update support
  
• Construct MBR (Master Boot Record) Partition Table
• Construct GPT (GUID Partition Table)
  

The Construct MBR and Construct GPT options serve the same purpose: they allow the exported partition to appear as a standard physical disk on the client side after the iSCSI initiator connects.
Without a valid partition table, the client operating system may encounter compatibility issues, as the device will not be recognized as a proper disk.
Choosing Between MBR and GPT

• Use MBR for partitions smaller than 2 TB
• Use GPT for partitions 2 TB or larger
• If the client system does not support GPT, select MBR
  

Windows includes a partition protection mechanism. When a partition (or physical disk) is exported to a client with full access, the server (iStorage Server) may still retain write permissions to the underlying device.

This can lead to issues on the client side, such as:

• Disk reported as not formatted
• Frequent errors in the system event log
  

To avoid these issues, use one of the following approaches:

• Enable Persistent Exclusive Access
  Recommended for scenarios where a single client performs data updates
  Ensures exclusive write access and prevents conflicts
  

• Enable Virtual Write Feature
  Suitable for multi-client shared access scenarios
  Configure clients to use temporary (buffered) writes
  
• Hold and Update
  Access with full access will automatically lock volume, and automatically unlock volume after log out.