Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : MySQL on Separate vs Same Server

[Heng Chai]

Just wondering about the performance difference between one powerful server vs two mid-grade servers. Experts and experienced users please comment and advise. Down to examples.

Running of a 10k user forum, 500 or more always on. Comparision of two different operation models.

1x Dual PIII 1GHz + 2GB RAM (Web & MySQL)
2x Single PIII 1Ghz + 1GB RAM (Web, MySQL)

All using SCSI 10K drives, same OS (which OS is irrelvant), MySQL compiled/configured with optimum settings (On the basis that both MySQL servers are compiled/configured the same way).

Factors To Consider

• Disk access (1 vs 2 servers)
• Network latency (8-11% slower based on MySQL documentation)

How would the performance compare in such a situation? Appreciate all comments on this discussion.

[phpdeveloper]

Put 2 SCSI drives on the dual PIII server, one for mysql databases, other - for everything else. 2 GB is good for making everything possible cacheable - mysql caching, php scripts caching. Still you'd feel better off with a dual xeon server. Dual PIII 1 Ghz may not do it too well. I would go the dual CPU server route. Forums are sites where the data can be stored in cache most of the time and retrieved quickly. It is updated more seldom than it is fetched for display. The dual CPU server can be fine-tuned for this application, provided you have 500 users online. You said more though, how many more? Up to 1000? Need more information.

[Heng Chai]

Actually, I'm looking at this on a theory basis, not really looking for optimising of hardware. I'm not actually running the forum of 500 users, its just an example for this situation.

CPU/RAM was chosen such that it would look like the Dual server split into two. Your suggestion 2x SCSI drives for the Dual sounds good, would make it a fairer comparision too. Thanks.

[hiryuu]

Yeah, the big-box topology would probably be better here. The system has access to the full 2gb, so it can cache more of one side of the other as it needs. (For instance, the split version would have ~600MB of web stuff cached, but it may be better off using 300MB for web and throwing the other 300 toward sql.)