Column HOT_USED_MB & COLD_USED_MB in V$ASM_DISKGROUP
What's the below two columns use for?
HOT_USED_MB
Number of used megabytes in the hot region
COLD_USED_MB
Number of used megabytes in the cold region you can do it all using a new attribute of diskgroup which allows two values: “hot” and “cold”. The former puts the data near the edges while the latter places it near the center. This is done via templates. Let’s define a template – hot_files – for those most accessed files.
alter diskgroup dg1 add template hot_files attributes (hot) / Diskgroup altered. Once the template is created, you can use it to create the datafiles using that template:
create tablespace hot_ts datafile '+DATA(hot_files)/hot_ts_01.dbf' size 1M / in a disk, the outer part have greater performance than the inner part. ---imagine a disk as your DVD or CD.
outer parts are called hot region and inner parts are called cold region.
oracle give you the flexibility to be able to place files in either hot or cold region. IF the geometry is not mask from ASM instance.
++++++++++++++The below is the db alert log file during startup, ASMB is the process from database to ASM instance communication for data write and read+++++++++++++
This instance was first to open
Starting background process ASMB
Tue Sep 06 23:54:44 2022
ASMB started with pid=35, OS id=5410
Tue Sep 06 23:54:44 2022
NOTE: ASMB registering with ASM instance as Standard client 0xffffffffffffffff (reg:1656733188) (new connection)
Starting background process RBAL
Tue Sep 06 23:54:44 2022
RBAL started with pid=36, OS id=5414
Tue Sep 06 23:54:44 2022
NOTE: Loaded library: /opt/oracle/extapi/64/asm/orcl/1/libasm.so
Tue Sep 06 23:54:44 2022
NOTE: ASMB connected to ASM instance +ASM1 osid: 5412 (Flex mode; client id 0xffffffffffffffff)
NOTE: initiating MARK startup
Starting background process MARK
++++++++++++++++++++++++++++++++++++++++++++++++++++++++
SQL> alter database datafile '+TESTDG/NMS/DATAFILE/testtbs.256.1114369479' offline;
Database altered.
SQL>
