| Harddisks considerations for better MySQL performance [message #343] |
Fri, 10 November 2006 15:42  |
 bitrockers
Messages: 11
Registered: November 2006
Location: Germany |
Junior Member |
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Hi all,
currently we're planning to purchase new servers for our website. A rough overview of our mysql-scenario:
665 Mio rows, 25G data, and 55G index files.
Average of 400 queries per seconds, 15% inserts, 9% updates, 1% deletes, 75% selects (on one slave, we're running 4 slaves overall).
We've choosen DELL PowerEdge 2950 machines, 2x dual core Intels (Woodcrest) with 8 GB RAM.
From a performance point of view: What Do you think would be better?
a) 2 x 146 GB SAS 15krpm disks as RAID 1
b) 4 x 73 GB SAS 15krpm disks, where we would put the index files on one partition, and the data files on the other? Would we gain a performance increase from that ? I've read something about that in the docs, but didn't saw any benchmarkings about that ?
c) 5 x 73 GB SAS disks on a RAID 5 ( more spindles) ?
What do you think?
And what is your opinion about the processors? Should we stick to a one-processor server (e.g. instead of 2 x dual core xeon 2.3 GHz -> 1 x dual core xeon 1.6), and invest the money to more RAM? Would that be a better investment?
Greetings
Christian
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| Re: Harddisks considerations for better MySQL performance [message #352 is a reply to message #343 ] |
Sun, 12 November 2006 22:19  |
Peter
Messages: 405
Registered: August 2006 |
Senior Member
Super Guru |
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Christian,
Yes Poweredge 2950 are pretty good. Much better than 2850 both from CPU performance and from RAID controller performance standpoint.
First I see you're getting it only with 8GB of RAM - at my opinion 16GB is sweetspot for this system - no overly expensive as larger memory systems.
In your case with data size relatively close to database size Memory is very likely to be best investment.
Regarding 1/2 CPUs it depens on how much CPU is the bottleneck in your system. If it is IO bound reducing IO will be most important for optimal performance.
Regarding disks. Of course 4-5 disks will be faster than 2 and 15K disks are faster than 10K. How much I can't tell as it really depends on your workload. If IO is going to be very intense with reads being most of the load 5 drives RAID5 will be probably fastest (for reads). RAID10 is more secure and faster for writes.
Peter Zaitsev, MySQL Performance Expert
MySQL Performance Blog - http://www.mysqlperformanceblog.com
MySQL Consulting http://www.mysqlperformanceblog.com/mysql-consulting/
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