Timestamps within ASM
Posted by John Hallas on April 2, 2009
Blogs are normally about how to resolve things or sharing some newly found information. In this case I am trying to resolve a question which I have struggled to understand for a while. It is concerned with the timestamps used within ASM.
An example is provided below. I switched the archive log three times at 7:31 and the logs numbers were 100,101,102
Looking in ASM I see the timestamps as 07:00
Fair enough, it is to the nearest hour, or to be more precise the first minute of the current hour and that is proved with another switch at 08:37
Now I look at datafiles and ls –lrt of the DATAFILES older shows the last few entries as
And this does not change after I take a checkpoint (alter system checkpoint).
I then take a tablespace off line and bring it back online which I would expect to update the file timestamp
Looking in ASM I note that some datafiles, including the datafile for the mis_SEP09 tablespaces has had the timestamp updated to 09:00 which is the first minute of the current hour and yet one file is timestamped at 01:00 and the rest are at midnight 00:00. I have not shown all the datafiles but the information below is sufficient to see why I am a bit mystified by it all. As I said at the beginning this is more of a blog seeking input so if anybody wishes to comment then feel free
This entry was posted on April 2, 2009 at 9:01 am and is filed under ASM, Oracle. Tagged: asmcmd, checkpoint, datafile, timestamp. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.