Re: Hardware spec

Jean-David Beyer wrote:
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> Willo van der Merwe wrote:
>
>> Richard Huxton wrote:
>>
>>> Willo van der Merwe wrote:
>>>
>>>> Hi guys,
>>>>
>>>> I'm have the rare opportunity to spec the hardware for a new database
>>>> server. It's going to replace an older one, driving a social
>>>> networking web application. The current server (a quad opteron with
>>>> 4Gb of RAM and 80Gb fast SCSI RAID10) is coping with an average load
>>>> of ranging between 1.5 and 3.5.
>>>>
>>>> The new machine spec I have so far:
>>>>
>>> What's the limiting factor on your current machine - disk, memory,
>>> cpup?
>>>
>> I'm a bit embarrassed to admit that I'm not sure. The reason we're
>> changing machines is that we might be changing ISPs and we're renting /
>> leasing the machines from the ISP.
>>
>>
> Before you get rid of the current ISP, better examine what is going on with
> the present setup. It would be good to know if you are memory, processor, or
> IO limited. That way you could increase what needs to be increased, and not
> waste money where the bottleneck is not.
>
Good advice. After running a vmstat and iostat, it is clear, to my mind
anyway, that the most likely bottleneck is IO, next is probably some
more RAM.
Here's the output:
procs -----------memory---------- ---swap-- -----io---- --system--
----cpu----
r b swpd free buff cache si so bi bo in cs us sy
id wa
0 0 29688 80908 128308 3315792 0 0 8 63 6 8 17
2 80 1

avg-cpu: %user %nice %sys %iowait %idle
17.18 0.00 1.93 0.81 80.08

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 14.57 66.48 506.45 58557617 446072213
sda1 0.60 0.27 4.70 235122 4136128
sda2 0.38 0.77 2.27 678754 2002576
sda3 2.37 0.49 18.61 429171 16389960
sda4 0.00 0.00 0.00 2 0
sda5 0.71 0.66 5.46 578307 4807087
sda6 0.03 0.01 0.24 6300 214196
sda7 0.02 0.00 0.19 2622 165992
sda8 60.19 64.29 474.98 56626211 418356226