OriglogA and MirrorlogA ---- freespace is not same

[Former Member]

Hi All,

Can any body please explain in brief, what origlogA and OriglogB contain?

As per my knowledge, MirrorlogA and MirrorlogB are the copies of OriglogA and B respectively.

But when I see the snapshot of my file system in ST06; then it shows freespace available for OriglogA = 20% and that for MirrorlogA = 23%

At the same time freespace available in OriglogB and MirrorlogB is same i.e. 23%.

Can anybody please tell me why is it so.

Thanks.

--Shamish

[Former Member · Accepted solution]

Hi Shamish,

Usually at a Oracle standard installation, there's a controlfile into OriglogA.

You can see at OS level, and, if necessary, change its location from initSID.ora file.

Best Regards,

JC Llanes.

[Former Member · Accepted solution]

Thanks Juan.

But can you suggest waht can be the reason for the different free space in OriglogA and MirrorlogA ?

--Shamish

[Former Member · Accepted solution]

Lele,

Assume Group1 ( A_LOG1 and B_LOG1) on Disk1

Group2 (A_LOG2 and B_LOG2) on Disk2

each member of a group is concurrently active, or, concurrently written to by LGWR, as indicated by the identical log sequence numbers assigned by LGWR. first LGWR writes to A_LOG1 in conjunction with B_LOG1, then A_LOG2 in conjunction with B_LOG2, and so on. LGWR never writes concurrently to members of different groups (for example, to A_LOG1 and B_LOG2).

Vinod

[Former Member · Accepted solution]

Thanks U,

But then how much delay will there be for A_LOG2 to get written after A_LOG1 has got written?

Since I can see the difference from more than three- four days.

( I had not noticed this before so keenly. hence don't for how long this status is there ).

--Shamish

[Former Member · Accepted solution]

Hi Shamish,

If there's a Controlfile into OriglogA, it isn't replicated to MirrlogA (it's just a "normal" file, not a Redolog). The size of this controlfile must be the difference of the filesystems free space.

Regards,

JC Llanes.

[Former Member · Accepted solution]

Thanks Juan,

It was such a simple thing that I missed out.!

Anyway... thanks for your help!

But Can you please also explain where and how does this file is used?

( I could not read that file )

--Shamish

Message was edited by:

Shamish Lele

[Former Member · Accepted solution]

Hi Shamish,

The oracle controlfile is a binary file containing all the DB structure and status. Without this file you can't start your oracle DB.

At your $ORACLE_HOME/dbs, you'll find the initSID.ora file. Into this file, there's a "control_files" param, with at least 2 destination paths. All the destinations included at this parameter must contain a controlfile at the DB start time.

You can find more info about it with an easy internet search "oracle controlfile".

Best Regards,

JC Llanes.

[Former Member · Accepted solution]

Thanks Juan!

--Shamish