Re: Data Guard Apply lag
- From: "A. Coskan Gundogar" <gundogar@xxxxxxxxx>
- To: Brandon.Allen@xxxxxxxxxxx
- Date: Tue, 6 Mar 2007 15:38:17 +0200
Do you have a delay for log transportation process or log apply process. If
it is about transportation maybe this calculation would give you an idea.
if it is about the applying process try to calculate from the formula below
and take action if you network is not satisfying for transportation process(
*Note:241925.1*);
Using a formula that allows for 30% network overhead and the known redo
rate, validate that your network bandwidth is sufficient to support the redo
rate. For example if we know the redo rate is 500 K/sec, then the following
calculation would be done:**
Required bandwidth
= ((Redo rate in bytes ps / .7) * 8) / 1,000,000
= bandwidth in Mbps
= ((500 * 1024) / .7) * 8) / 1,000,000
= 5.85 Mbps
Thus, in this example a 10 Mbps network or a T3 network (44.736 Mbps )
should have plenty of bandwidth whereas a T1-DS1 network (1.544 Mbps) would
not be sufficient for this redo rate. Also playing into this capacity is
what else is using this link.
If it is about the delay for applying process then maybe you should try to
parellize the applying process by clause below
"alter database recover managed standby database parallel X disconnect "
i think value of X was
max(X)=number_of_cpu*2
another option is Set DB_BLOCK_CHECKING=FALSE for Faster Redo Apply Rates
and another one Set PARALLEL_EXECUTION_MESSAGE_SIZE = 4096
also if you do not have async i/o increasing db_writer process will help
you
http://download-east.oracle.com/docs/cd/B19306_01/server.102/b14239/manage_ps.htm#i1033033
On 3/5/07, Allen, Brandon <Brandon.Allen@xxxxxxxxxxx> wrote:
DELAY is the parameter I was talking about - here is the link and
example from further down on the same page as the link you sent:
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96653/log_
arch_dest_param.htm#77475
LOG_ARCHIVE_DEST_3='SERVICE=stby1 DELAY=240'
LOG_ARCHIVE_DEST_STATE_3=ENABLE
-----Original Message-----
From: GovindanK [mailto:gkatteri@xxxxxxxxxxx]
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96653/log_
arch_dest_param.htm#82634
Example log_archive_dest_2="SERVICE=tns_entry_here ARCH NOAFFIRM
OPTIONAL REOPEN=seconds"
Which version/platform is this problem occuring?
HTH
GovindanK
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A. Coskan GUNDOGAR
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