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Pem Emineva avatar image
Pem Emineva asked

Log shipping setup and High CPU usage

Dear all, I'm concerned with the following issue: After the setup of Log shipping on high -intensive system, running on SQL Server 2005 Enterprise EDition SP4, there is 100 % CPU usage SQL Server average CPU - above 90 on the primary server and also high intensive I/O caused by SQL Server. In this relation I wanted to ask you whether you have experienced some problems with the performance of the primary server after the Logshipping setup - as I/O high and CPU high and where exactly could be the cause? Log shippping so far as I read would have a little or no impact on the application performance on the primary server. There is no large Transaction log and also after disabling of Log shipping at 11:00 a.m the problem remains till 18:00 p.m ( in the intensive work hours with the system). All session are from the IIS. Thanks in advance. I would be very thankful If somebody could explained exactly how Log shiiping impacts the performance of the primary server and which is the cause nad eventually the solution.
performancelog-shippinglog
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Pem Emineva avatar image Pem Emineva commented ·
Thanks to all for the answers. That was exactly the case : Large number of transactions in specific period of the day : above 50 000 permanently, but daily the average number of transactions sent by application is permanent enormous and the problem doesn't exist, because there are permanently processed by SQL Server. In this situation something caused I/O bottleneck and the processing was slow by SQL Server. After disabling Log shipping the situation remains the same for 6 hours, but the reason was ( already not processed application transactions). Now the situation is normal, but Log shipping is disabled we have only the normal Transaction log backup plan and I will look further if Log shipping leads to slower executing of application transactions ( especially the transfer of Transaction log backups when they become bigger to the other server). I will check these days the network and I/O processing before setup it again in the production. Thanks a lot again.
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salum avatar image
salum answered
There should not be any performance impact due to logshipping on primary server as log backup is a normal process and copy and restore job at secondry server.
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TimothyAWiseman avatar image TimothyAWiseman commented ·
I think saying it won't have any impact is going a bit far since it still adds some work to the server. But the work it adds to the primary server and the impact it has should both be minimal. You normally wouldn't notice.
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Usman Butt avatar image
Usman Butt answered
Although log shipping add some overhead of taking log backups after specific interval but in most transaction processing environments, taking transaction log backups is necessary and normal, so I do not think that it would be the problem. But Log shipping does add some disk and network overhead since it has to copy the backup files to the standby server periodically. If you have a large number of transactions you should check your network and disk performance. I believe this will lead you to the root cause.
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Pem Emineva avatar image
Pem Emineva answered
I configured before 2 weeks Log shipping without Monitor server again, and now is running. The performance on the primary server is ok after the second setup. Thanks to all for the replies and the motivation to setup Log shipping again. ( The performance issue was caused by extensive I/O workload by Application Windows service.
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