Re: Oracle Server will write continually to control files.

In article <cs3kt30mg8_at_news3.newsguy.com>, Orlando Amador says...
>
>
>"Thomas Kyte" <tkyte_at_oracle.com> wrote in message
>news:115545437.0001662e.017_at_drn.newsguy.com...
>> In article <cs3h0f0ja3_at_news3.newsguy.com>, Orlando Amador says...
>> >
>> >We have a Oralce 9.2 Standard database server with multiple database
>> >instances. Each instance has 2 control files, although in the same
>> >directory.
>> >
>> >Using a file monitor we find that the server will write a block of 8K to
>> >offset 24576 of the control files every 3 seconds. I wonder if this some
>> >kind of synchronization, locking, or heartbeat function in the database.
>> >The accumulated IO from the writes from a single database is not a
>problem,
>> >but the accumulation from multiple database is creating problem for our
>> >backup software (Veritas BackupExec with OFO).
>>
>>
>> how is this creating a program for backup software?
>>
>
>Veritas BackupExec Open File Option requires a minimun quite time. Because
>if the constant writes it is not able to acchive the minimun quite window.
>
>>
>> file system backups of controlfiles for open database are "not useful" --
>they
>> shouldn't be touching them while the database is up.
>>
>
>The have agents for performing hot backup of the data, redo, and control
>files. That is not the issue here. There are other non-Data files on the
>same drive we are trying to backup.
>
>
>> You aren't "backing up" your databases with this stuff are you? (if so --
>it is
>> probable that you have nothing valid to restore with)...
>>
>
>You are correct, we are not.
>
>
>Any ideas on how to reduce the frequency of this writes?
>

there are none, it works the way it works. seems this would be an issue of the backup software here, that is cannot backup any files on a disk where any activity is taking place?

You should be excluding all DATABASE related files from this sort of backup for the following reasons:

1. they are useless, you cannot use them for anything
2. you can actually cause the databases to shutdown. I had someone say "my database goes down every morning at 3am -- why?" -- turns out every morning at 3am, their backup software would come along and lock the controlfile to "back it up" (well, really just copy a bunch of useless bytes to a backup device). This prevents us from writing to our controlfiles -- bamm, down database
3. it isn't working for you (perhaps most important of all).

Exclude the database stuff and veritas with the "open file option" should be happy as a clam.

>>
>>
>>
>>
>> >
>> >We figure that we can repartition this server and separate the databases
>in
>> >separate disk, but we are saving that as a last resort. I was hopping
>> >someone could point me to the reason of this updates and if there is a
>way
>> >to configure the timing? Maybe this is a required function but it could
>be
>> >slow down a bit? This updates happens constantly, even when the database
>is
>> >not in use and there is no connections.
>> >
>> >Any suggestions?
>> >
>> >11:39:33 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL01.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >11:39:33 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL02.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >11:39:37 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL01.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >11:39:37 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL02.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >11:39:40 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL01.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >11:39:40 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL02.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >11:39:43 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL01.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >11:39:43 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL02.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >11:39:46 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL01.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >11:39:46 AM oracle.exe:1128 WRITE D:\oracle\oradata\ISODEV\CONTROL02.CTL
>> >SUCCESS Offset: 24576 Length: 8192
>> >
>> >Saludos
>> >Orlando Amador
>> >
>> >
>> >
>>
>>
>> --
>> Thomas Kyte
>> Oracle Public Sector
>> http://asktom.oracle.com/
>> opinions are my own and may not reflect those of Oracle Corporation
>
>

-- 
Thomas Kyte
Oracle Public Sector
http://asktom.oracle.com/
opinions are my own and may not reflect those of Oracle Corporation