DUMPTMIN parameter - Revision history

JAL at 19:17, 12 August 2014

2014-08-12T19:17:02Z

← Older revision		Revision as of 19:17, 12 August 2014
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	<dd>System manager resettable		<dd>System manager resettable
	<dt>Related products		<dt>Related products
	<dd>[[Fast/Backup]]		<dd>[http://m204wiki.rocketsoftware.com/images/1/12/FastbackNew.pdf Fast/Backup]
	<dt>Introduced		<dt>Introduced
	<dd>Before <var class="product">Sirius Mods</var> 6.7		<dd>Before <var class="product">Sirius Mods</var> 6.7
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	and the thread needs to update a page that has not been dumped yet,		and the thread needs to update a page that has not been dumped yet,
	that page needs to be dumped before the page can be updated.		that page needs to be dumped before the page can be updated.
	Normally, ''Fast/Backup'' will dump such a page almost immediately, and		Normally, Fast/Backup will dump such a page almost immediately, and
	there will be no noticeable delay for the updating transaction.		there will be no noticeable delay for the updating transaction.
	However, if ''Fast/Backup'' is waiting for a tape volume switch, perhaps waiting		However, if Fast/Backup is waiting for a tape volume switch, perhaps waiting
	for a tape mount, an updating transaction in this scenario would		for a tape mount, an updating transaction in this scenario would
	also have to wait for the tape mount.		also have to wait for the tape mount.
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	are timed out.		are timed out.

	In such a situation, ''Fast/Backup'' will try to copy the page to be updated to CCATEMP,		In such a situation, Fast/Backup will try to copy the page to be updated to CCATEMP,
	allowing the updating thread to continue with its update.		allowing the updating thread to continue with its update.
	After the tape mount is satisfied, the page is copied from CCATEMP, and the		After the tape mount is satisfied, the page is copied from CCATEMP, and the
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	The DUMPTMIN parameter indicates the minimum number of CCATEMP pages that must		The DUMPTMIN parameter indicates the minimum number of CCATEMP pages that must
	be free, that is, available to other applications, before ''Fast/Backup'' will use one		be free, that is, available to other applications, before Fast/Backup will use one
	to cache a page that is about to be updated.		to cache a page that is about to be updated.
	If this number of pages is not available in the scenario described above, the		If this number of pages is not available in the scenario described above, the
	updating thread will have to wait for the tape mount, or the dump		updating thread will have to wait for the tape mount, or the dump
	will be terminated with an error, depending on the setting of the [[DUMPOPTS parameter]].		will be terminated with an error, depending on the setting of the <var>[[DUMPOPTS parameter\|DUMPOPTS]]</var> parameter.

	The default value for DUMPTMIN of 0 means that no limit is placed on		The default value for <var>DUMPTMIN</var> of 0 means that no limit is placed on
	the use of CCATEMP pages by ''Fast/Backup''.		the use of CCATEMP pages by Fast/Backup.

			See also <var>[[DUMPTMAX parameter\|DUMPTMAX]]</var>.

	~~See also [[DUMPTMAX parameter\|DUMPTMAX]].~~
	[[Category:System parameters]]		[[Category:System parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

DmeWiccan: Automatically generated page update

2013-08-27T16:26:03Z

Automatically generated page update

← Older revision		Revision as of 16:26, 27 August 2013
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			{{Template:DUMPTMIN parameter subtitle}}
	==Summary==		==Summary==
	<dl>		<dl>

DmeWiccan: 1 revision

2012-06-22T19:25:00Z

1 revision

New page

==Summary==
<dl>
<dt>Default value
<dd>0
<dt>Parameter type
<dd>System
<dt>Where set
<dd>System manager resettable
<dt>Related products
<dd>[[Fast/Backup]]
<dt>Introduced
<dd>Before <var class="product">Sirius Mods</var> 6.7
</dl>
==Description==
This parameter sets the minimum number of free
CCATEMP pages that must be available for DUMP to use one for pre-imaging
when waiting for second or subsequent tape volume mounts.

If a thread is performing an update on a file that is being dumped,
and the thread needs to update a page that has not been dumped yet,
that page needs to be dumped before the page can be updated.
Normally, ''Fast/Backup'' will dump such a page almost immediately, and
there will be no noticeable delay for the updating transaction.
However, if ''Fast/Backup'' is waiting for a tape volume switch, perhaps waiting
for a tape mount, an updating transaction in this scenario would
also have to wait for the tape mount.
The result is not good for the updating request, and potentially not good
for other users in the Online, as resources held by the updating user are
not released, and if sub-transaction checkpoints are being used, checkpoints
are timed out.

In such a situation, ''Fast/Backup'' will try to copy the page to be updated to CCATEMP,
allowing the updating thread to continue with its update.
After the tape mount is satisfied, the page is copied from CCATEMP, and the
CCATEMP used by the cached page is freed.
Obviously, if there is a lot of updating for a file being dumped, and the dump
ends up waiting on a tape mount, this could result in a '''lot''' of
CCATEMP being used, leaving insufficient CCATEMP for other applications.

The DUMPTMIN parameter indicates the minimum number of CCATEMP pages that must
be free, that is, available to other applications, before ''Fast/Backup'' will use one
to cache a page that is about to be updated.
If this number of pages is not available in the scenario described above, the
updating thread will have to wait for the tape mount, or the dump
will be terminated with an error, depending on the setting of the [[DUMPOPTS parameter]].

The default value for DUMPTMIN of 0 means that no limit is placed on
the use of CCATEMP pages by ''Fast/Backup''.

See also [[DUMPTMAX parameter|DUMPTMAX]].
[[Category:System parameters]]
[[Category:Parameters]]

JAL at 01:07, 1 October 2010

2010-10-01T01:07:21Z

← Older revision		Revision as of 01:07, 1 October 2010
Line 47:		Line 47:
	the use of CCATEMP pages by ''Fast/Backup''.		the use of CCATEMP pages by ''Fast/Backup''.

	See also [[DUMPTMAX parameter\|DUMPTMAX~~]] and [[DUMPOPTS parameter\|DUMPOPTS~~]].		See also [[DUMPTMAX parameter\|DUMPTMAX]].
	[[Category:System Parameters]]		[[Category:System Parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

JAL at 21:03, 30 September 2010

2010-09-30T21:03:37Z

New page

<dl>
<dt>Default value
<dd>0
<dt>Parameter type
<dd>System
<dt>Where set
<dd>System manager resettable
<dt>Related products
<dd>[[Fast/Backup]]
<dt>Introduced
<dd>Before [[Sirius Mods]] 6.7
</dl>

This parameter sets the minimum number of free
CCATEMP pages that must be available for DUMP to use one for pre-imaging
when waiting for second or subsequent tape volume mounts.

If a thread is performing an update on a file that is being dumped,
and the thread needs to update a page that has not been dumped yet,
that page needs to be dumped before the page can be updated.
Normally, ''Fast/Backup'' will dump such a page almost immediately, and
there will be no noticeable delay for the updating transaction.
However, if ''Fast/Backup'' is waiting for a tape volume switch, perhaps waiting
for a tape mount, an updating transaction in this scenario would
also have to wait for the tape mount.
The result is not good for the updating request, and potentially not good
for other users in the Online, as resources held by the updating user are
not released, and if sub-transaction checkpoints are being used, checkpoints
are timed out.

In such a situation, ''Fast/Backup'' will try to copy the page to be updated to CCATEMP,
allowing the updating thread to continue with its update.
After the tape mount is satisfied, the page is copied from CCATEMP, and the
CCATEMP used by the cached page is freed.
Obviously, if there is a lot of updating for a file being dumped, and the dump
ends up waiting on a tape mount, this could result in a '''lot''' of
CCATEMP being used, leaving insufficient CCATEMP for other applications.

The DUMPTMIN parameter indicates the minimum number of CCATEMP pages that must
be free, that is, available to other applications, before ''Fast/Backup'' will use one
to cache a page that is about to be updated.
If this number of pages is not available in the scenario described above, the
updating thread will have to wait for the tape mount, or the dump
will be terminated with an error, depending on the setting of the [[DUMPOPTS parameter]].

The default value for DUMPTMIN of 0 means that no limit is placed on
the use of CCATEMP pages by ''Fast/Backup''.

See also [[DUMPTMAX parameter|DUMPTMAX]] and [[DUMPOPTS parameter|DUMPOPTS]].
[[Category:System Parameters]]
[[Category:Parameters]]