Erasing Data from Disks

Prerequisites

• The storage system is running properly.
• To ensure user data security, data on member disks in a disk domain cannot be erased.
• To erase data from a faulty disk in a disk domain, perform the following operations:
  • If there are vacant slots in the storage system, you are advised to replace the faulty disk with a functional one, insert the faulty disk into a vacant slot, and then erase data as instructed in this section. For details about how to replace a disk, see the Parts Replacement.
  • If there is no vacant slot in the storage system, contact Huawei technical support engineers.

Precautions

• This section describes how to erase data from disks using DeviceManager. This operation erases user data but retains disk authentication information. After data is erased, the disks can still be used. If you want to perform full erasure (which makes a disk unavailable), run the change disk erase command. For details about this command, see the Advanced O&M Command Reference for Block.

• Disks whose data is being erased cannot be added to a disk domain.
• Data on unreadable and unwritable disks cannot be erased.
• Some disks do not support some data erasing mechanisms. If you attempt to erase data from such disks, the storage system returns error code. For details, see How Do I Determine Which Data Erasing Mechanisms Are Supported By a Disk?
• For a storage system in a non-Kunpeng version (such as V500R007C60), if data erasure is interrupted due to a power failure or other factors, restart the storage system, enter the minisystem view, and run the erase_disk_data.sh command to resume the data erasure task. For details about how to enter the minisystem view and how use the erase_disk_data.sh command, see the Advanced O&M Command Reference for Block.
• Do not run any commands for clearing configuration during data erasing, including ccdb.sh -c clearccdb, ccdb.sh -c cleardbfile, ccdb.sh -c operdb, ccdb.sh -c recoverymd, ccdb.sh -c repairdb, change ccdb general, restore system factory_mode, change cluster controllers, change controllers_expansion cancel, and clear configuration_data.

Procedure

1. Log in to DeviceManager.
2. Click System.
3. Select a controller enclosure or disk enclosure in the left navigation tree and then select disks for data erasure.
4. Erase data from the disks.
   1. In the lower part of the window, click Erase Data.

      If one of the selected disks is a disk in a disk domain, the Erase Data option is unavailable.

      The Erase Data dialog box is displayed.

   2. Set parameters.

      For details about the parameters, see Table 5-54.

      Table 5-54 Data erasure parameters

      Parameter	Description	Value
      Data Erasure Mechanism	Data erasure mechanism. Possible values are as follows: block_erase: Implements block-level data erasure. cryptographic_erase: Erases security keys. NOTE: This parameter applies only to SEDs. overwrite: Writes specific hexadecimal numbers to overwrite disk data.	[Example] overwrite
      Data Erasure Standard	Standard with which the overwrite data erasure mechanism complies. Possible values are DoD 5220.22-M (E), DoD 5220.22-M (ECE), VSITR, and Custom. NOTE: This parameter is valid only when Data Erasure Mechanism is set to overwrite. If Data Erasure Standard is set to custom, the system overwrites disk data according to the Pattern Value and Number of Overwrites set by a user. DoD 5220.22-M (E): DoD 5220.22-M standard that enables a storage system to write 0x55, 0xAA, and a pseudo random number in sequence. DoD 5220.22-M (ECE): DoD 5220.22-M (ECE) standard that enables a storage system to write 0x55, 0xAA, a pseudo random number, a pseudo random number, 0x55, 0xAA, and a pseudo random number in sequence. VSITR: VSITR standard that enables a storage system to write 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, and a pseudo random number in sequence. Custom: User-defined standard. You can customize the hexadecimal numbers to be written and the number of write times.	[Example] custom
      Pattern Value	A one-byte pattern value used to overwrite disk data. NOTE: This parameter is valid only when Data Erasure Mechanism is set to overwrite and Data Erasure Standard is set to Custom. The value can be r or a hexadecimal number starting with 0x, both of which occupy one byte. A maximum of three values can be entered and separated by commas (,). When Pattern Value is set to r, it represents a random number.	[Example] 0x00
      Number of Overwrites	Number of times that disk data is overwritten by Pattern Value. NOTE: This parameter is valid only when Data Erasure Mechanism is set to overwrite and Data Erasure Standard is set to Custom.	[Value range] 1 to 15 [Example] 5
      Verify Data Erasure	Indicates whether to enable data erasure verification. If this function is enabled, the system checks whether the data has been erased after executing data erasure. NOTE: This parameter is valid only when Data Erasure Mechanism is set to overwrite or block_erase. The speed of verifying SSD data erasure is about 200 MB/s to 350 MB/s. Estimate the verification time and then determine whether to enable verification or select a proper percentage of data to be verified. You can view the data erasure report to check whether data is successfully erased. If the value of Result in the report is succeeded, data is successfully erased. For details, see Exporting a Data Erasure Report.	[Default] Disable
      Data to Be Verified (%)	Percentage of to-be-verified data size to the total capacity of a disk. NOTE: This parameter is valid only when Data Erasure Mechanism is set to overwrite or block_erase and Verify Data Erasure is set to Enable.	[Value range] 1 to 100 [Default] 10

5. Click OK.

   A Danger dialog box is displayed.

6. Confirm the content in the dialog box, enter I have read the preceding information and understood consequences of the operation. as prompted, and click OK.

   If Verify Data Erasure is set to Enable, another Danger dialog box will be displayed. Confirm the content in the dialog box, select I have read and understand the consequences associated with performing this operation., and click OK.

   The Execution Result dialog box is displayed, indicating that the operation is successful.

7. Click Close.