| PRIMECLUSTER Global Disk Services Configuration and Administration Guide 4.1 (Linux) |
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Contents
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| Appendix A General Notes | > A.2 Important Points |
After registration of disks with GDS is complete, accessing the disks using physical special files as below becomes impossible. GDS prevents unintentional access by the users to physical special files in order to protect mirroring statuses.
/dev/sdXn (for normal hard disk)
/dev/emcpowerXn (for emcpower devices)
X is a lowercase alphabetic character that indicates the device ID, and n is the slice number.
For example, if you execute the dd command to write to a disk using a physical special file, an error as below occurs.
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# dd if=/dev/zero of=/dev/sda1 |
The disk list output by the parted(8) command does not display disks registered with GDS.
This access protection is canceled when a disk is removed from a class. It will also be canceled when an object is used for disk swap. The access protection function will turn back on if disk recovery operation is performed on the object.
Access to physical special files is prevented on the following nodes:
For disks that are registered with disk classes
When registered with the PRIMECLUSTER's resource database
All of the nodes in the relevant domains
When not registered with the PRIMECLUSTER's resource database
Nodes where the relevant disk classes (root classes or local classes) reside
For disks that are registered with shadow classes
Nodes where the relevant shadow classes reside
For the following disks, access to physical special files is not prevented. Be careful not to access these physical special files.
Disks that are registered with classes in other domains
Disks that are registered with root classes or local classes on other nodes and for which disk resources are not registered with the resource database
Disks that are registered with shadow classes on other nodes
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