Re: redo per second (size)on exadata ?
From: David Fitzjarrell <oratune_at_yahoo.com>
Date: Tue, 2 Sep 2014 10:50:14 -0700
Message-ID: <1409680214.42759.YahooMailNeo_at_web124702.mail.ne1.yahoo.com>
If she really means 80 mb per second on the redo generation that would generated a large number of log switches; presuming you are using the recommended redo log size of 4gb we're talking one log switch every 50 seconds. You're not restricted to 4 gb logs so if this is anticipated to be the 'normal' traffic on your OLTP system you might want to consider even larger logs. My guess on this is the 80 mb per second isn't the redo rate, it's the transaction rate and that could mean less actual redo volume generated. You really need to clarify what this 80 mb per second rate really means. David Fitzjarrell Principal author, "Oracle Exadata Survival Guide" On Thursday, August 28, 2014 10:06 AM, "Powell, Mark" <mark.powell2_at_hp.com> wrote: I imagine that the redo rate varies greatly between systems. How you looked to see what your past rate or redo generation happens to be? You ought to be able to use that as a comparison number or baseline. My main system appears to only generate between 30G – 40G of redo per day across both nodes. I have several other systems that generate far less. From:oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of amihay gonen Sent: Thursday, August 28, 2014 6:55 AM To: ORACLE-L Subject: redo per second (size)on exadata ? Hi all, I've been asked by our VP to give estimation what is consider heavy system OLTP in term of redo per bytes rate. She told to to test our exadata machine with load of 80Mb per second per Node , and I've told her that I think it is too much . if OLTP system with generate 80Mb* (2 nodes) per second that it means 576G per hour . I wonder if anyone work with such systems , what is the typical redo rate ? thanks amihay
Date: Tue, 2 Sep 2014 10:50:14 -0700
Message-ID: <1409680214.42759.YahooMailNeo_at_web124702.mail.ne1.yahoo.com>
If she really means 80 mb per second on the redo generation that would generated a large number of log switches; presuming you are using the recommended redo log size of 4gb we're talking one log switch every 50 seconds. You're not restricted to 4 gb logs so if this is anticipated to be the 'normal' traffic on your OLTP system you might want to consider even larger logs. My guess on this is the 80 mb per second isn't the redo rate, it's the transaction rate and that could mean less actual redo volume generated. You really need to clarify what this 80 mb per second rate really means. David Fitzjarrell Principal author, "Oracle Exadata Survival Guide" On Thursday, August 28, 2014 10:06 AM, "Powell, Mark" <mark.powell2_at_hp.com> wrote: I imagine that the redo rate varies greatly between systems. How you looked to see what your past rate or redo generation happens to be? You ought to be able to use that as a comparison number or baseline. My main system appears to only generate between 30G – 40G of redo per day across both nodes. I have several other systems that generate far less. From:oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of amihay gonen Sent: Thursday, August 28, 2014 6:55 AM To: ORACLE-L Subject: redo per second (size)on exadata ? Hi all, I've been asked by our VP to give estimation what is consider heavy system OLTP in term of redo per bytes rate. She told to to test our exadata machine with load of 80Mb per second per Node , and I've told her that I think it is too much . if OLTP system with generate 80Mb* (2 nodes) per second that it means 576G per hour . I wonder if anyone work with such systems , what is the typical redo rate ? thanks amihay
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