Re: Disable flashback in either shutdown or nomount mode?
- From: Don Seiler <don@xxxxxxxxx>
- To: Seth Miller <sethmiller.sm@xxxxxxxxx>
- Date: Wed, 8 Oct 2014 13:58:58 -0500
Actually I found these options given to us by the Oracle ZFSSA or DNFS team:
rw,bg,hard,tcp,nfsvers=3,timeo=600,rsize=1048576,wsize=1048576,nointr,noatime
Trying those first. Not sure why we hadn't propagated those to the other
systems by now.
Don.
On Wed, Oct 8, 2014 at 1:43 PM, Don Seiler <don@xxxxxxxxx> wrote:
> I did forget to mention that this is on 11.2.0.3.
>
> Also this problem only seems to occur when starting our STAGING database
> which is on NFS (direct NFS) on the ZFSSA. With our DEV database on ASM we
> don't see this problem.
>
> I just did a long overdue review of our NFS mount options. They were:
>
> defaults,rw,noatime,bg,hard,tcp,nfsvers=3,timeo=600,rsize=1048576,wsize=1048576,noacl
>
> I changed them to:
>
> rw,bg,hard,nointr,tcp,vers=3,timeo=600,rsize=1048576,wsize=1048576,actimeo=0
>
> We'll see how it goes this weekend.
>
> On Tue, Oct 7, 2014 at 9:21 PM, Don Seiler <don@xxxxxxxxx> wrote:
>
>> It is creating the flashback log as part of the mounting process. Here is
>> the alert log snippet that I'm basing this on:
>>
>> Sun Sep 21 09:40:38 2014
>> Successful mount of redo thread 3, with mount id 4175062721
>> Sun Sep 21 10:23:02 2014
>> Allocated 331130296 bytes in shared pool for flashback generation buffer
>> Starting background process RVWR
>> Sun Sep 21 10:23:02 2014
>> RVWR started with pid=28, OS id=69631
>> Database mounted in Exclusive Mode
>> Lost write protection disabled
>> Completed: alter database mount
>> Sun Sep 21 10:23:15 2014
>> alter database flashback off
>> Stopping background process RVWR
>> Deleted Oracle managed file
>> /mnt/foo/fra/FOO/flashback/o1_mf__1411306838866824_.flb
>> Flashback Database Disabled
>> Completed: alter database flashback off
>>
>> You can see the 43 minute delay between the mount of the last redo thread
>> and the flashback generation buffer. During that time I see the flashback
>> .flb log file being written to on the NFS mount. When that finishes, the
>> database is mounted and flashback is immediately disabled (per the script).
>>
>> Don.
>>
>>
>> On Tue, Oct 7, 2014 at 9:09 PM, Seth Miller <sethmiller.sm@xxxxxxxxx>
>> wrote:
>>
>>> Don,
>>>
>>> Are you saying that the instance is creating a flashback log before it
>>> is mounted?
>>>
>>> How did you come to the conclusion that it is the log creation causing
>>> the wait?
>>>
>>> Seth Miller
>>>
>>>
>>> On Tuesday, October 7, 2014, Don Seiler <don@xxxxxxxxx> wrote:
>>>
>>>> Good evening,
>>>>
>>>> Part of my staging/dev refresh process involves taking an image copy
>>>> backup of prod datafiles and controlfiles and firing up a new instance from
>>>> them. The first thing I do when mounting the new database is to turn off
>>>> flashback. However recently we're seeing that the time to mount takes
>>>> almost 40 minutes while the instance creates a new flashback log. Seems
>>>> silly to have to wait for this when we plan to disable it right away
>>>> anyway.
>>>>
>>>> Is there a way to disable flashback database without having to mount?
>>>> I'm guessing the worst case scenario is having to create a trace of the
>>>> controlfile and create a new one with flashback disabled.
>>>>
>>>> Don.
>>>>
>>>> --
>>>> Don Seiler
>>>> http://www.seiler.us
>>>>
>>>
>>
>>
>> --
>> Don Seiler
>> http://www.seiler.us
>>
>
>
>
> --
> Don Seiler
> http://www.seiler.us
>
--
Don Seiler
http://www.seiler.us
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