I'd been listening with a moderate amount of amusement, but it's now getting
out of hand ... (9iR2 & W2K)

One of the local DBAs has his heart set on nightly shutdowns to do cold
backups. Another DBA wants to go for online backups. (Archive logging is
up and active.)

The debate has gone all over silly territory and back and is now at:
"Shutting down the database will waste all the automatic tuning benefits
achieved from the system finding stability in the cache, etc.. It can take
hours, even months to get the system stable."

Does anyone have pointers to documents, white papers, books, web sites,
metalink note, etc. that I can drop on their desks to move them off this
'shutdown detunes the database' discussion?

Due to politics, I will not provide an opinion or even make a supportable
statement in either direction. This needs to be an external (to me)
reference, and preferrably not an unsupported anecdote.

(Once they're over this, I hope the discussion can get back to a pure
business benefits discussion!)

Thanks in Advance for helping control the local noise pollution!
/Hans

Hans Forbrich wrote:

> I'd been listening with a moderate amount of amusement, but it's now
> getting out of hand ... (9iR2 & W2K)
>
> One of the local DBAs has his heart set on nightly shutdowns to do cold
> backups. Another DBA wants to go for online backups. (Archive logging is
> up and active.)
>
> The debate has gone all over silly territory and back and is now at:
> "Shutting down the database will waste all the automatic tuning benefits
> achieved from the system finding stability in the cache, etc.. It can
> take hours, even months to get the system stable."
>
> Does anyone have pointers to documents, white papers, books, web sites,
> metalink note, etc. that I can drop on their desks to move them off this
> 'shutdown detunes the database' discussion?
>
> Due to politics, I will not provide an opinion or even make a supportable
> statement in either direction. This needs to be an external (to me)
> reference, and preferrably not an unsupported anecdote.
>
> (Once they're over this, I hope the discussion can get back to a pure
> business benefits discussion!)
>
> Thanks in Advance for helping control the local noise pollution!
> /Hans

Good luck with finding that sort of material.

Personally, and I realise this is not what you were after, I would simply
ask "*what* automatic tuning benefits actually exist in 9i R2??". Because
apart from the PGA, there aren't any that I can think of!

DBMS_SHARED_POOL.KEEP and a suitable after startup trigger will "pre-warm"
the library cache.

The buffer cache will be cold, so physical reads will be needed to
re-populate it, true enough. But we know that a 100% buffer cache hit ratio
means nothing, and so a 0% hit ratio won't mean much either. And there's
LOTS of information out there on that particular topic!!

Ultimately, the only thing they can really do to sort this argument out is
to run some performance tests after one or two shutdowns, and compare with
normal "after several hours, even months" performance.

And the guy advocating cold backups should be asked why he wants to do cold
backups in the first place, given that he's in archivelog mode and has the
choice... is it just a convenience thing? A lack of skills thing? A "I
don't really know RMAN too well" thing? Or what??

Regards
HJR

Howard J. Rogers wrote:

> Hans Forbrich wrote:
>
> Good luck with finding that sort of material.
>
> Personally, and I realise this is not what you were after, I would simply
> ask "*what* automatic tuning benefits actually exist in 9i R2??". Because
> apart from the PGA, there aren't any that I can think of!
>
> DBMS_SHARED_POOL.KEEP and a suitable after startup trigger will "pre-warm"
> the library cache.
>
> The buffer cache will be cold, so physical reads will be needed to
> re-populate it, true enough. But we know that a 100% buffer cache hit
> ratio means nothing, and so a 0% hit ratio won't mean much either. And
> there's LOTS of information out there on that particular topic!!
>
> Ultimately, the only thing they can really do to sort this argument out is
> to run some performance tests after one or two shutdowns, and compare with
> normal "after several hours, even months" performance.
>
> And the guy advocating cold backups should be asked why he wants to do
> cold backups in the first place, given that he's in archivelog mode and
> has the choice... is it just a convenience thing? A lack of skills thing?
> A "I don't really know RMAN too well" thing? Or what??
>
> Regards
> HJR

Bingo - I think you hit it. I think the 'shutdown detunes' DBA want to use
ratio-based tuning. (The other DBA ... 'we have always done it that way'!)

<sigh>
/Hans

Hans Forbrich <news.hans@telus.net> wrote in message news:<KDK8d.32806$N%.31956@edtnps84>...

> One of the local DBAs has his heart set on nightly shutdowns to do cold
> backups. Another DBA wants to go for online backups. (Archive logging is
> up and active.)

Ay!...... been there, done that.

> The debate has gone all over silly territory and back and is now at:
> "Shutting down the database will waste all the automatic tuning benefits
> achieved from the system finding stability in the cache, etc.. It can take
> hours, even months to get the system stable."

Gross exageration, the "months" thing. IMHO. Never ever saw
such a case. It either is a very weird load system or someone
is on vapours...


> Does anyone have pointers to documents, white papers, books, web sites,
> metalink note, etc. that I can drop on their desks to move them off this
> 'shutdown detunes the database' discussion?

I don't think you'll find anything in that area, but...

>
> (Once they're over this, I hope the discussion can get back to a pure
> business benefits discussion!)
>

Weeeeelll, is it worth even letting it move away from the business
benefits?

My point is: cold backups vs hot backups is a decision that should
be based only on business requirements: does the business require
24X7 operation? If yes, then hot backups is the only option.
If not then cold backups (if there is enough window) are
an equaly valid option.

My personal choice would be RMAN, but in Windows that may
pose some minor problems. At least I've had some in the past.
Mostly due to my lack of deep knowledge about it in that environment.

Cold backups is a good one in that environment. Particularly if
hardware assisted: shadow volumes, yadda yadda.
I hate to use the old chestnut. So I'll just say
it is highly contingent on the business requirements
and pretty much little else...

**** Post for FREE via your newsreader at post.usenet.com ****

Noons wrote:

> Hans Forbrich <news.hans@telus.net> wrote in message
news:<KDK8d.32806$N%.31956@edtnps84>...

>> One of the local DBAs has his heart set on nightly shutdowns to do cold
>> backups. Another DBA wants to go for online backups. (Archive logging is
>> up and active.)

> Ay!...... been there, done that.

>> The debate has gone all over silly territory and back and is now at:
>> "Shutting down the database will waste all the automatic tuning benefits
>> achieved from the system finding stability in the cache, etc.. It can take
>> hours, even months to get the system stable."

> Gross exageration, the "months" thing. IMHO. Never ever saw
> such a case. It either is a very weird load system or someone
> is on vapours...


>> Does anyone have pointers to documents, white papers, books, web sites,
>> metalink note, etc. that I can drop on their desks to move them off this
>> 'shutdown detunes the database' discussion?

> I don't think you'll find anything in that area, but...

>>
>> (Once they're over this, I hope the discussion can get back to a pure
>> business benefits discussion!)
>>

> Weeeeelll, is it worth even letting it move away from the business
> benefits?

> My point is: cold backups vs hot backups is a decision that should
> be based only on business requirements: does the business require
> 24X7 operation? If yes, then hot backups is the only option.
> If not then cold backups (if there is enough window) are
> an equaly valid option.

> My personal choice would be RMAN, but in Windows that may
> pose some minor problems. At least I've had some in the past.
> Mostly due to my lack of deep knowledge about it in that environment.

> Cold backups is a good one in that environment. Particularly if
> hardware assisted: shadow volumes, yadda yadda.
> I hate to use the old chestnut. So I'll just say
> it is highly contingent on the business requirements
> and pretty much little else...

The business requirements and available backup resources are the key here.
A cold backup offers the advantage over a hot backup of being a
consistent point in time recovery all by itself if the forward recovery
runs into an issue accessing the archived redo logs. However, if the
archived redo logs are being written to a separate disk from the database
files and online logs then the only real risk involved with forward
recovery is running into redo log corruption.

I would suggest using hot backups throught the week and perhaps making a
cold backup over the weekend if time permitted.

IMHO -- Mark D Powell --






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Mark D Powell wrote:

>
> The business requirements and available backup resources are the key here.
> A cold backup offers the advantage over a hot backup of being a
> consistent point in time recovery all by itself if the forward recovery
> runs into an issue accessing the archived redo logs. However, if the
> archived redo logs are being written to a separate disk from the database
> files and online logs then the only real risk involved with forward
> recovery is running into redo log corruption.
>
> I would suggest using hot backups throught the week and perhaps making a
> cold backup over the weekend if time permitted.

Totally agree with all the responses that say 'stick with the business
reasons'.

However ... like any internet flame war, the two involved are getting
stoopid and any attempt to reason things out will result in sideline
participants getting burned. Only things to do are walk or throw on a pail
of water - in the form of white papers - to help put out the flames. Once
the silliness is over, we can get back to the true business reasons.

/Hans

> My point is: cold backups vs hot backups is a decision that should
> be based only on business requirements: does the business require
> 24X7 operation? If yes, then hot backups is the only option.
> If not then cold backups (if there is enough window) are
> an equaly valid option.

Tom Kyte makes the point that light bulbs typically burn out when the
switch is turned on, and computer systems are most likely to fail while
being restarted. My personal experience with 25 years of computer and
control systems agrees with that observation. Every time your DBA shuts
down for a cold backup he is increasing, not decreasing, the chances of
data loss.

Even running 8.0 under NT4 we only reboot every 30 days (which is about
all NT can take). If you don't need the features of Oracle (e.g. hot
backup) why not talk to your salesrep about getting a letter of approval
to sell your Oracle licenses and use PostgreSQL instead? It is a lot
cheaper.

sPh

Hans Forbrich <news.hans@telus.net> wrote in message news:<KDK8d.32806$N%.31956@edtnps84>...
> I'd been listening with a moderate amount of amusement, but it's now getting
> out of hand ... (9iR2 & W2K)
>
> One of the local DBAs has his heart set on nightly shutdowns to do cold
> backups. Another DBA wants to go for online backups. (Archive logging is
> up and active.)
>
> The debate has gone all over silly territory and back and is now at:
> "Shutting down the database will waste all the automatic tuning benefits
> achieved from the system finding stability in the cache, etc.. It can take
> hours, even months to get the system stable."

http://download-west.oracle.com/docs...ools.htm#28104
might be an argument against shutting down, and for creating OMS. And
as long as you have that, you might as well have an RMAN catalog, and
all that other management stuff and modern features.

>
> Does anyone have pointers to documents, white papers, books, web sites,
> metalink note, etc. that I can drop on their desks to move them off this
> 'shutdown detunes the database' discussion?

http://download-west.oracle.com/docs...ro.htm#1005206
might shift the conversation over to "gee, I'd sure like to have these
features."
Like corrupt block detection, and
http://download-west.oracle.com/docs...ary.htm#432645
avoiding fractured block issues while still being able to run
overnight/month-end reports or other things that a growing business
might run into.

>
> Due to politics, I will not provide an opinion or even make a supportable
> statement in either direction. This needs to be an external (to me)
> reference, and preferrably not an unsupported anecdote.
>
> (Once they're over this, I hope the discussion can get back to a pure
> business benefits discussion!)
>
> Thanks in Advance for helping control the local noise pollution!
> /Hans

I'm with Mark on the nightly RMANs and weekly cold's, it seems to
cover most situations.

jg
--
@home.com is bogus.
A real Grundfest: http://www.zdnet.com.au/news/busines...9162206,00.htm

Joel Garry wrote:

> Hans Forbrich <news.hans@telus.net> wrote in message
> news:<KDK8d.32806$N%.31956@edtnps84>...
>> I'd been listening with a moderate amount of amusement, but it's now
>> getting out of hand ... (9iR2 & W2K)
>>
>> One of the local DBAs has his heart set on nightly shutdowns to do cold
>> backups. Another DBA wants to go for online backups. (Archive logging
>> is up and active.)
>>
>> The debate has gone all over silly territory and back and is now at:
>> "Shutting down the database will waste all the automatic tuning benefits
>> achieved from the system finding stability in the cache, etc.. It can
>> take hours, even months to get the system stable."
>
>
http://download-west.oracle.com/docs...ools.htm#28104
> might be an argument against shutting down, and for creating OMS. And
> as long as you have that, you might as well have an RMAN catalog, and
> all that other management stuff and modern features.
>
>>
>> Does anyone have pointers to documents, white papers, books, web sites,
>> metalink note, etc. that I can drop on their desks to move them off this
>> 'shutdown detunes the database' discussion?
>
>
http://download-west.oracle.com/docs...ro.htm#1005206
> might shift the conversation over to "gee, I'd sure like to have these
> features."
> Like corrupt block detection, and
>
http://download-west.oracle.com/docs...ary.htm#432645
> avoiding fractured block issues while still being able to run
> overnight/month-end reports or other things that a growing business
> might run into.
>
>>
>> Due to politics, I will not provide an opinion or even make a supportable
>> statement in either direction. This needs to be an external (to me)
>> reference, and preferrably not an unsupported anecdote.
>>
>> (Once they're over this, I hope the discussion can get back to a pure
>> business benefits discussion!)
>>
>> Thanks in Advance for helping control the local noise pollution!
>> /Hans
>
> I'm with Mark on the nightly RMANs and weekly cold's, it seems to
> cover most situations.
>
> jg

Thanks all. I got the diversion I needed to get them back on track.

From Howard's response I realized the core was a 'tuning by ratios'
discussion. I printed off some of the NG's thread around the 'value of
ratio-based tuning' [ ;-Q ] from a few months ago. That diverted their
attention and the discussion is now proceeding smoothly toward RMAN and
nightly warms.

/Hans

Hans Forbrich wrote:

> Joel Garry wrote:
>
>> Hans Forbrich <news.hans@telus.net> wrote in message
>> news:<KDK8d.32806$N%.31956@edtnps84>...
>>> I'd been listening with a moderate amount of amusement, but it's now
>>> getting out of hand ... (9iR2 & W2K)
>>>
>>> One of the local DBAs has his heart set on nightly shutdowns to do cold
>>> backups. Another DBA wants to go for online backups. (Archive logging
>>> is up and active.)
>>>
>>> The debate has gone all over silly territory and back and is now at:
>>> "Shutting down the database will waste all the automatic tuning benefits
>>> achieved from the system finding stability in the cache, etc.. It can
>>> take hours, even months to get the system stable."
>>
>>
>
http://download-west.oracle.com/docs...ools.htm#28104
>> might be an argument against shutting down, and for creating OMS. And
>> as long as you have that, you might as well have an RMAN catalog, and
>> all that other management stuff and modern features.
>>
>>>
>>> Does anyone have pointers to documents, white papers, books, web sites,
>>> metalink note, etc. that I can drop on their desks to move them off this
>>> 'shutdown detunes the database' discussion?
>>
>>
>
http://download-west.oracle.com/docs...ro.htm#1005206
>> might shift the conversation over to "gee, I'd sure like to have these
>> features."
>> Like corrupt block detection, and
>>
>
http://download-west.oracle.com/docs...ary.htm#432645
>> avoiding fractured block issues while still being able to run
>> overnight/month-end reports or other things that a growing business
>> might run into.
>>
>>>
>>> Due to politics, I will not provide an opinion or even make a
>>> supportable
>>> statement in either direction. This needs to be an external (to me)
>>> reference, and preferrably not an unsupported anecdote.
>>>
>>> (Once they're over this, I hope the discussion can get back to a pure
>>> business benefits discussion!)
>>>
>>> Thanks in Advance for helping control the local noise pollution!
>>> /Hans
>>
>> I'm with Mark on the nightly RMANs and weekly cold's, it seems to
>> cover most situations.
>>
>> jg
>
> Thanks all. I got the diversion I needed to get them back on track.
>
> From Howard's response I realized the core was a 'tuning by ratios'
> discussion. I printed off some of the NG's thread around the 'value of
> ratio-based tuning' [ ;-Q ] from a few months ago. That diverted their
> attention and the discussion is now proceeding smoothly toward RMAN and
> nightly warms.
>
> /Hans



LOL!!!

:-O
HJR