7.7.6.2 DROP CELL
Purpose
The DROP CELL
command resets a cell to its original state.
Syntax
DROP CELL [ERASE = value] [FORCE]
Usage Notes
-
This command is run from within the cell.
-
All cell disks, grid disks, and thresholds are dropped. The interdatabase plan is reset to its default state. All cell attributes are set to default values.
-
The
FORCE
option is required if the grid disks are configured on any cell disks whenDROP CELL
is issued. Otherwise, an error is reported. -
Flash cache compression must be disabled before securely erasing a drive.
-
The
ERASE
option erases the content on the disk by overwriting the content. The values are as follows:-
1pass
: One pass, and the content is overwritten with zeros. This value is not available for flash drives. -
3pass
: Three passes, and the content is overwritten with set data patterns. This option follows the recommendations of NNSA. This value is not available for flash drives. -
7pass
: Seven passes, and the disk is overwritten with set data patterns. This option follows the recommendations from DOD.
-
-
When dropping all cells using the
1pass
or3pass
option, it necessary to drop the flash disks first using the7pass
option, and then drop the cells. The following is an example of the commands:CellCLI> DROP CELLDISK ALL FLASHDISK ERASE=7pass CellCLI> DROP CELL ERASE=1pass
-
Starting with Oracle Exadata System Software release 19.1.0, if you specify to erase hard disks or flash disks using
1pass
,3pass
, or7pass
method on Oracle Exadata Database Machine X5 or later, Oracle Exadata System Software automatically invokes Secure Eraser to erase the disks. Secure Eraser determines whether or not the disks can be erased using the better and faster cryptographic erasure method. If some of the disks are eligible, then the cryptographic erasure method is used to erase those disks, and the originally requested method (1/3/7 pass) is used on the other disks. This feature is not used on system disks.See Table 7-3 for a list of the erasure methods available for each type of device.
The following table shows approximate time needed to securely erase a drive using the supported algorithms. When multiple grid disks or cell disks are dropped with the ERASE
option, the command runs in parallel on all disks and flash drives. However, the recommended method of erasing data from a cell is to use Secure Erase. See Securely Erasing Database Servers and Storage Servers in Oracle Exadata Database Machine Security Guide.
Table 7-2 Estimated Erasure Times for Devices by Erasure Method
Type of Device | 1pass | 3pass | 7pass | Cryptographic |
---|---|---|---|---|
600 GB hard drive |
1 hour |
3 hours |
7 hours |
not available |
1.2 TB hard drive |
1.67 hours |
5 hours |
11.67 hours |
not available |
2 TB hard drive |
5 hours |
15 hours |
35 hours |
not available |
3 TB hard drive |
7 hours |
21 hours |
49 hours |
not available |
4 TB hard drive |
8 hours |
24 hours |
56 hours |
not available |
8 TB hard drive |
13.17 hours |
39.5 hours |
92.17 hours |
1 min |
10 TB hard drive |
14 hours |
42 hours |
98 hours |
1 min |
14 TB hard drive |
18 hours |
54 hours |
126 hours |
1 min |
22.875 GB flash drive |
not available |
not available |
21 minutes |
not available |
93 GB flash drive |
not available |
not available |
32 minutes |
not available |
186 GB flash drive |
not available |
not available |
36 minutes |
not available |
1.6 TB flash drive |
not available |
not available |
5.5 hours |
1 min |
3.2 TB flash drive |
not available |
not available |
8 hours |
1 min |
Persistent Memory (PMEM) device |
not available |
not available |
not available |
1 min |
4 GB Internal USB |
not available |
30 minutes |
not available |
not available |
8 GB Internal USB |
not available |
1 hour |
not available |
not available |
150 GB M.2 device |
not available |
not available |
not available |
1 minute |
ILOM |
not available |
not available |
not available |
1 minute |
Example 7-126 Dropping a Cell
CellCLI> DROP CELL FORCE
Related Topics
Parent topic: DROP