Re: New server setup

On 10 March 2013 15:58, Greg Smith <greg(at)2ndquadrant(dot)com> wrote:

> On 3/1/13 6:43 AM, Niels Kristian Schjødt wrote:
>
>> Hi, I'm going to setup a new server for my postgresql database, and I am
>> considering one of these: http://www.hetzner.de/hosting/**
>> produkte_rootserver/poweredge-**r720<http://www.hetzner.de/hosting/produkte_rootserver/poweredge-r720>with four SAS drives in a RAID 10 array. Has any of you any particular
>> comments/pitfalls/etc. to mention on the setup? My application is very
>> write heavy.
>>
>
> The Dell PERC H710 (actually a LSI controller) works fine for write-heavy
> workloads on a RAID 10, as long as you order it with a battery backup unit
> module. Someone must install the controller management utility and do
> three things however:
>
> We're going to go with either HP or IBM (customer's preference, etc).

> 1) Make sure the battery-backup unit is working.
>
> 2) Configure the controller so that the *disk* write cache is off.
>
> 3) Set the controller cache to "write-back when battery is available".
> That will use the cache when it is safe to do so, and if not it will bypass
> it. That will make the server slow down if the battery fails, but it won't
> ever become unsafe at writing.
>
> See http://wiki.postgresql.org/**wiki/Reliable_Writes<http://wiki.postgresql.org/wiki/Reliable_Writes>for more information about this topic. If you'd like some consulting help
> with making sure the server is working safely and as fast as it should be,
> 2ndQuadrant does offer a hardware benchmarking service to do that sort of
> thing: http://www.2ndquadrant.com/en/**hardware-benchmarking/<http://www.2ndquadrant.com/en/hardware-benchmarking/> I think we're even generating those reports in German now.

Thanks Greg. I will follow advice there, and also the one in your book. I
do always make sure they order battery backed cache (or flash based, which
seems to be what people use these days).

I think subject of using external help with setting things up did came up,
but more around connection pooling subject then hardware itself (shortly,
pgpool2 is crap, we will go with dns based solution and apps connection
directly to nodes).
I will let my clients (doing this on a contract) know that there's an
option to get you guys to help us. Mind you, this database is rather small
in grand scheme of things (30-40GB). Just possibly a lot of occasional
writes.

We wouldn't need German. But Proper English (i.e. british english) would
always be nice ;)

Whilst on the hardware subject, someone mentioned throwing ssd into the
mix. I.e. combining spinning HDs with SSD, apparently some raid cards can
use small-ish (80GB+) SSDs as external caches. Any experiences with that ?

Thanks !

--
GJ