We're all mostly limited in IOPS, so the amount / speed of spindles matters a lot, as does having SAS drives that have larger queues.
So, normally 8 small SAS drives > 4 larger SAS drives > 8 SATA drives.
With 16GB Ram you can expect to run 15-30 VPS depending on how much memory they get to see (or more with openVZ). Usually the bottlenecks are memory and disk IO performance. You could opt to add more SAS drives once you hit 40% system usage.
If you want a hint: Look up how the Linux IO schedulers work (deadline and cfq with priority classes)
Check out my SSD guides for Samsung, HGST (Hitachi Global Storage) and Intel!
I'd go with the SAS drives too, and I'd add some RAM. Your bottleneck will probably be disk IO but people want high RAM even if they're not going to use it all.
The SAS drives will be faster, and I've found them to be much more reliable as well, since they're built primarily for server use.
★ Sam Barrow - CEO @ SQUIDIX(1-855-SQUIDIX)
★ Ask Us About Sponsoring Your Web Site (High Traffic Sites Only)
★ Squidix - Shared, Reseller, Semi-Dedicated, Managed VPS and Managed Dedicated Hosting
★ Midwestern Web - Web Design & Development Services
Okay, I will take 24GB instead of 16GB RAM and 4 SAS drives instead of 8 SATA2 drives. Thanks for your help.
I'm planning to run at least 30 VPS's there, otherwise I will have a clean loss considering this server will cost me 400-500eur a month.
Also, for the best experience shall I allocate my client all CPU's(equal share) or allocate 1 or 2 CPU's per VPS? In the past my old VPS provider suspended my VPS for causing high load to the node, and I had to upgrade to plan 2 with 2 cores. After that everything was ok. So basically, can VPS's with 1 core cause issues to VPS Node?
There is also something what bothers me. On my another provider they said I'm causing high load and moved me to less-loaded node, where I wasn't causing high load. How is that possible?