A long time ago, I had blogged about SQL Versus ASMCMD
You may be thinking that I must be crazy for wanting to compare datafiles.
Here’s the story. Oracle database is running on Amazon EBS volume.
The objective is to shutdown existing standby database, take a snapshot of EBS volume, create new volume from snapshot, and present the volume to 2 new standby hosts.
The 2 standby hosts will be added to existing Data Guard configuration.
One of the new standby hosts will be converted to primary database and upgraded to 19c using dbua.
Before taking snapshot, standby database was shutdown and checked for no opened files from ASM diskgroup.
$ asmcmd lsof -G DATA
DB_Name Instance_Name Path
$ asmcmd lsof -G REDO
DB_Name Instance_Name Path
$ asmcmd lsof -G FRA
DB_Name Instance_Name Path
$ asmcmd lsof -G BACKUP
DB_Name Instance_Name Path
So why is it necessary to compare datafiles?
There were issues with mounting the new volume from snapshots and wanted to verify there were no lurking issues.
After all, the 2 new standby databases should be identical.
There are 583 datafiles and how would you have compared them?
$ sdiff -iEZbWBs -w 100 ora01-prod_DATA.txt ora02-prod_DATA.txt
[oracle@ora01-prod ~]$ asmcmd ls DATA/*/ | [oracle@ora02-prod ~]$ asmcmd ls DATA/*/*/*
[oracle@ora01-prod ~]$ | [oracle@ora02-prod ~]$
$ wc -l ora01-prod_DATA.txt; wc -l ora02-prod_DATA.txt
583 ora01-prod_DATA.txt
583 ora02-prod_DATA.txt
I used asmcmd ls DATA/*/*/* , copy output to text file, and compare the text file.
Q.E.D.