Where's the bottleneck?

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Posted by JetJaguar, 05-17-2011, 04:31 PM
We have two database systems, and a certain large query is 20 seconds on one, and about 45 seconds on the other. The query is just a lookup of all the accounts with a certain master account id, which is the primary key. It returns about 35,000 lines. What do you think may be the bottleneck in the slower of the two systems, as described below?: System 1 SLOWER: Oracle Linux in Oracle VM. Box not taxed by other vms. Oracle 10g DB LSI hw raid 6, enterprise SATA drives actual datastore is on a netapp FAS270, FC drives, raid 4, connected by nfs, 100baseT System 2, FASTER: Oracle Linux in Oracle VM. Box not taxed by other vms. Oracle 10g DB software raid 6 (mdadm) enterprise SATA drives
Posted by arunns, 05-17-2011, 04:37 PM
Software RAID is slower than hardware raid since it is done on the OS level. How about the memory installed on those servers and the utilization. ./arun
Posted by JetJaguar, 05-17-2011, 04:38 PM
I would love to see data supporting this. Not assertions, but hard data.
Posted by JetJaguar, 05-17-2011, 04:41 PM
Anyway, the software raid system is the FASTER one. That's why I put FASTER in capital letters in its description.
Posted by arunns, 05-17-2011, 04:50 PM
If you system is utilized badly that can impact the software RAID performance unlike the hardware raid. The performance of software RAID always depends on the system resources and CPU. Google for some benchmarking done.
Posted by UNIXy, 05-17-2011, 06:02 PM
Local disks especially with RAID (even with SW RAID) always beats NFS. Even more so for the fact that NFS store is connected via 100. How much data are you pulling from the DB? You mentioned 35000 lines. What's the byte size? Regards Joe / UNIXy