Em 25/11/16 11:29, Miloslav Hůla escreveu:

Hi,

we are planning to change hardware for our standalone Dovecot instance handling ~5800 IMAP users with 1TB mailboxes on local RAID. Is there some recommendation about CPU?

We can choose from:

• Intel Xeon E5-2620v4 - 2,1GHz@8,0GT 20MB cache, 8core, HT, 85W, LGA2011
• Intel Xeon E5-2623v4 - 2,6GHz@8,0GT 10MB cache, 4core, HT, 85W, LGA2011

The difference is about more cores vs. hi frequency.

 Generally speaking, servers will benefith from more cores instead 

of faster cores. Servers usually are doing LOTS of things, and thus more cores use to be better.

 Unless you know you'll be doing something heavily CPU intensive, 

which generally mail related things are not.

 Even more important than choosing more cores x higher frequency, 

you should focus on faster I/O. This, specially on mail servers, can do a REAL difference !

--

Atenciosamente / Sincerily,
Leonardo Rodrigues
Solutti Tecnologia
http://www.solutti.com.br

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Den 25. nov. 2016 14:29, skrev Miloslav Hůla:

Hi,

we are planning to change hardware for our standalone Dovecot instance handling ~5800 IMAP users with 1TB mailboxes on local RAID. Is there some recommendation about CPU?

We can choose from:

• Intel Xeon E5-2620v4 - 2,1GHz@8,0GT 20MB cache, 8core, HT, 85W, LGA2011
• Intel Xeon E5-2623v4 - 2,6GHz@8,0GT 10MB cache, 4core, HT, 85W, LGA2011

The difference is about more cores vs. hi frequency. As far as I can see, high frequency costs more than more cores, so the 2623 is more geared towards interactive use, or single-threaded servers (like a single java thread). 50% reduction in number of cores gets you only a few percent increase in frequency. Go with 2620 for mail server.