Could someone tell me what would be the perfect configuration for a hosting server, running apache/mysql/php/ftp/ssh/pop/imap/smtp and hosting lets say a minimum of 100 clients?

Also lets say the clients are small companies or just people, not a lot of hits on their webpages and normal or usual amount of mails.

I am asking in hardware... which would work perfectly. Please let me know if u might have some ideas on this.

Also both way VPS specs and/or physical hardware specs.

If possible include the distro which you would go for.

I am running now something like that and its an Intel Pentium Dual-Core 3.2Ghz (4MB cache), 4GB DDR2667, 200GB SATA disk, UPS and so on.

The system is running on Ubuntu Server 8.04 (i386).

Thanks in advance.

I doubt that there is any single answer to the perfect configuration, although there may be many answers to what is a good enough configuration.

Is that really an old Pentium D-something-or-another (netburst arch), or is it a Core 2 Duo arch part (E-something-or-another)? If its one of the old pentium Ds then would be a weak point. The E's aren't really pentiums, except for the E2xxx series and they don't have anywhere near that amount of cache.

But the disk bandwidth seems unlikely to cope if the that had many sql databsaes with even only moderate traffic each, so that would be a weak point, too.

processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 6
model name : Intel(R) Pentium(R) D CPU 3.20GHz
stepping : 5
cpu MHz : 2400.000
cache size : 2048 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 6
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm constant_tsc pebs bts sync_rdtsc pni monitor ds_cpl est cid cx16 xtpr lahf_lm
bogomips : 6424.86
clflush size : 64

processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 6
model name : Intel(R) Pentium(R) D CPU 3.20GHz
stepping : 5
cpu MHz : 2400.000
cache size : 2048 KB
physical id : 0
siblings : 2
core id : 1
cpu cores : 2
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 6
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm constant_tsc pebs bts sync_rdtsc pni monitor ds_cpl est cid cx16 xtpr lahf_lm
bogomips : 6420.25
clflush size : 64

Hmm the disk i wouldnt say its an issue...

Your best bet is to monitor your existing hardware and see if its up to the task. If not, then identify the bottleneck. IO, Memory, CPU, Disk Capacity, Network....

iostat
vmstat
top
df
du
netstat -i