Re: Speed / Server

On Mon, Oct 5, 2009 at 7:30 AM, Nikolas Everett <nik9000@gmail.com> wrote:
>
>> But you should plan on partitioning to multiple db servers up front
>> and save pain of conversion later on.  A dual socket motherboard with
>> 16 to 32 SAS drives and a fast RAID controller is WAY cheaper than a
>> similar machine with 4 to 8 sockets is gonna be.  And if you gotta go
>> there anyway, might as well spend your money on other stuff.
>>
>
> I agree.  If you can partition that sensor data across multiple DBs and have
> your application do the knitting you might be better off.  If I may be so
> bold, you might want to look at splaying the systems out across your
> backends.  I'm just trying to think of a dimension that you won't want to
> aggregate across frequently.

Agreed back.  If there's a logical dimension to split data on, it
becomes much easier to throw x machines at it than to try and build
one ubermachine to handle it all.

> On the other hand, one of these 16 to 32 SAS drive systems with a raid card
> will likely get you a long way.

Yes they can.  We're about to have to add a third db server, cause
this is the load on our main slave db:

procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
22  0    220 633228 229556 28432976    0    0   638   304    0    0 21
 3 73  3  0
19  1    220 571980 229584 28435180    0    0    96  1111 7091 9796 90
 6  4  0  0
20  0    220 532208 229644 28440244    0    0   140  3357 7110 9175 90
 6  3  0  0
19  1    220 568440 229664 28443688    0    0   146  1527 7765 10481
90  7  3  0  0
 9  1    220 806668 229688 28445240    0    0    99   326 6661 10326
89  6  5  0  0
 9  0    220 814016 229712 28446144    0    0    54  1544 7456 10283
90  6  4  0  0
11  0    220 782876 229744 28447628    0    0    96   406 6619 9354 90
 5  5  0  0
29  1    220 632624 229784 28449964    0    0   113   994 7109 9958 90
 7  3  0  0

It's working fine.  This has a 16 15k5 SAS disks.  A 12 Disk RAID-10,
a 2 disk mirror for pg_xlog / OS, and two spares. It has 8 opteron
cores and 32Gig ram. We're completely CPU bound because of the type of
app we're running.  So time for slave number 2...