Re: How/when does Oracle know when to start ASMB background process?
From: Tanel Poder <tanel_at_tanelpoder.com>
Date: Fri, 18 Jan 2013 22:27:58 +0200
Message-ID: <CAMHX9JLcb8bmx0a6Nsyo3GWEhTKHEm2qKGeCkO+2TQxdk_meRA_at_mail.gmail.com>
One addition:
ASM is just a block address translation layer and these translations are cached in SGA, the actual IO is still done by the regular Oracle instance processes. ASM is just consulted for finding out where the blocks physically reside - and this info is cached in DB instance's SGA - shows up as "ASM extent pointer array" in V$SGASTAT.
Date: Fri, 18 Jan 2013 22:27:58 +0200
Message-ID: <CAMHX9JLcb8bmx0a6Nsyo3GWEhTKHEm2qKGeCkO+2TQxdk_meRA_at_mail.gmail.com>
One addition:
ASM is just a block address translation layer and these translations are cached in SGA, the actual IO is still done by the regular Oracle instance processes. ASM is just consulted for finding out where the blocks physically reside - and this info is cached in DB instance's SGA - shows up as "ASM extent pointer array" in V$SGASTAT.
-- Tanel Poder Online Training! - http://blog.tanelpoder.com/seminar The Voicee App - http://voic.ee On Fri, Jan 18, 2013 at 10:05 PM, Tanel Poder <tanel_at_tanelpoder.com> wrote:Received on Fri Jan 18 2013 - 21:27:58 CET
> I haven't looked into this, but they could be just started on demand -
> whenever a client function calls any of the kfk functions requiring ASM
> connection (like populating the ASM extent pointer array etc).
>
> There's a wait event "ASM background starting" for this I think ... Note
> that ASMB processes also quit after some time period (defined by
> _asm_wait_time). So we can assume that more processes will be started on
> demand.
>
> --
> Tanel Poder
> Online Training! - http://blog.tanelpoder.com/seminar
> The Voicee App - http://voic.ee
>
>
> On Thu, Jan 17, 2013 at 5:26 PM, <Christopher.Taylor2_at_parallon.net> wrote:
>
>> I know this may seem rudimentary to many of you, but another DBA and I
>> were discussing this question. (After I recently dorked up an spfile on one
>> of my QA clustes - miscalculating sga_max_size)
>> So we were talking and I was curious how (or when) does Oracle know to
>> start the ASMB background process when starting up from a pfile when no
>> spfile is specified in the pfile?
>>
>> I have to "assume" that because the control files have the "+" notation
>> that the instance knows to start the ASMB process?
>>
>> I've tried verifying this on my own but couldn't put my hands on the
>> answer right away.
>>
>> Regards,
>>
>> Chris Taylor
>> Oracle DBA
>> Parallon IT&S
>>
>>
>> --
>> http://www.freelists.org/webpage/oracle-l
>>
>>
>>
>
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