7.7.4.9 CREATE PMEMLOG
Purpose
The CREATE PMEMLOG
command creates the persistent memory (PMEM) log
on a cell for redo log write requests.
Note:
The CREATE PMEMLOG
command can only be used on
Exadata X8M and X9M storage server models.
Syntax
CREATE PMEMLOG { ALL [ size=log_size ] |
CELLDISK='cdisk1[,cdisk2]...' [ , size=log_size ] }
Usage Notes
-
The
ALL
argument creates the PMEM log on all PMEM cell disks. If theALL
argument is not specified, then specific PMEM cell disks must be specified by using theCELLDISK
argument. The PMEM log is spread as evenly as possible across the PMEM cell disks. -
PMEM log space is allocated in 16 MB chunks, referred to as allocation units, with a minimum of 1 allocation unit. Consequently, when the
size
argument is specified, the actual space allocated to the PMEM log is at least 16 MB or the largest multiple of 16 MB that is less than or equal to the specified size. For example, ifsize=300M
is specified, then 288 MB is allocated using 18 allocation units. -
If a size is not specified, then a default size is used. Commencing with Oracle Exadata System Software version 20.1.0, the default size is 10176 MB (9.9375 GB). Previously, the default size was 960 MB.
-
To change the size of the PMEM log, use the
DROP PMEMLOG
command to drop the PMEM log, and then use theCREATE PMEMLOG
command to create a PMEM log with the new size. -
On Exadata X8M and X9M systems with Oracle Exadata System Software release 23.1.0, you can interchangeably use
CREATE XRMEMLOG
instead ofCREATE PMEMLOG
.
Note:
By default, theCREATE
PMEMCACHE
command uses all available space on each PMEM cell disk.
Therefore, it is recommended to create the PMEM log before the PMEM Cache to ensure
that both objects are accommodated.
Examples
The following example shows how to create the PMEM log on a cell.
Example 7-89 Creating the PMEM Log
To create the PMEM log using the default size spread across all available PMEM cell disks, use the following command:
CellCLI> CREATE PMEMLOG ALL
To create the PMEM log with a size of 1 GB spread across all available PMEM cell disks, use the following command:
CellCLI> CREATE PMEMLOG ALL SIZE=1g
To create the PMEM log using the default size spread across specific PMEM cell disks, use the following command:
CellCLI> CREATE PMEMLOG CELLDISK='PM_01_mycell,PM_02_mycell,PM_03_mycell,PM_04_mycell'
To create the PMEM log with a size of 1 GB spread across specific PMEM cell disks, use the following command:
CellCLI> CREATE PMEMLOG CELLDISK='PM_01_mycell,PM_02_mycell,PM_03_mycell,PM_04_mycell', size=1G
Parent topic: CREATE