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Re: New hardware thoughts

From: "Bucky Jordan" <bjordan(at)lumeta(dot)com>
To: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>,"Ben Suffolk" <ben(at)vanilla(dot)net>
Cc: "Dave Cramer" <pg(at)fastcrypt(dot)com>,<pgsql-performance(at)postgresql(dot)org>
Subject: Re: New hardware thoughts
Date: 2006-10-22 18:59:39
Message-ID: 78ED28FACE63744386D68D8A9D1CF5D4209D5A@MAIL.corp.lumeta.com (view raw or flat)
Thread:
Lists: pgsql-performance
> -----Original Message-----
> From: pgsql-performance-owner(at)postgresql(dot)org
[mailto:pgsql-performance-
> owner(at)postgresql(dot)org] On Behalf Of Joshua D. Drake
> Sent: Friday, October 20, 2006 2:52 PM
> To: Ben Suffolk
> Cc: Dave Cramer; pgsql-performance(at)postgresql(dot)org
> Subject: Re: [PERFORM] New hardware thoughts
> 
> Ben Suffolk wrote:
> >> You mentioned a "Perc" controller, so I'll assume this is a Dell.
> >>
> >> My advice is to find another supplier. check the archives for Dell.
> >>
> >> Basically you have no idea what the Perc controller is since it is
> >> whatever Dell decides to ship that day.
> >>
> >> In general though you are going down the right path here. Disks
first,
> >> memory second, cpu third
> >>
> >> Dave
> >
> > Yes I am looking at either the 2950 or the 6850. I think the only
think
> > that the 6850 really offers me over the 2950 is more expandability
in
> > the spare processor, and additional memory
> > sockets. In all other respects the config I am looking at would fit
> > either chassis. Although the 2950, being slightly newer has the DRAC
5
> > (dells implementation of IPMI) management, which may be useful.
> 
> Get an HP with the 64* series. They are a good, well rounded machine
for
> PostgreSQL.
> 
> http://h10010.www1.hp.com/wwpc/pscmisc/vac/us/en/ss/proliant/proliant-
>
dl.html?jumpid=re_R295_prodexp/busproducts/computing-server/proliant-dl
> 
> > I hear what you say about the raid card, but how likely are they to
> > change it from the LSI Mega Raid one in reality? But I am open to
> 
> Heh... very likely. I have a 6 drive Dell machine with a Perc
controller
> (lsi rebrand). If I put it in RAID 5, it refuses to get more than 8
megs
> a second. If I put it in RAID 10, it get about 50 megs a second.
> 
> If I get the offshelf LSI Megaraid withe the same configuration? You
> don't want to know... it will just make you want to cry at the fact
that
> you bought a Dell.

I agree there's better platforms out there than Dell, but the above is
simply not true for the 2950. Raid 5, dd, on 6 disks, I get about
260Mb/s sustained writes. Granted, this should be faster, but... it's a
far cry from 8 or 50MB/s. I posted some numbers here a while back on the
2950, so you might want to dig those out of the archives. 

For CPU, if that's a concern, make sure you get Woodcrest with 4MB
shared cache per socket. These are extremely fast CPU's (Intel's 80%
performance improvements over the old Xeons actually seem close). Oh,
and I would NOT recommend planning to add CPU's to a dell box after
you've purchased it. I've seen too many CPU upgrades go awry. Adding
disks, no biggie, adding ram, eh, don't mind, adding CPU, I try to stay
away from for reliability purposes.

Also, I have had experience with at least half dozen 2850's and 2950's -
all have had the LSI controllers re-branded as Perc. If this is a
concern, talk with dell, and I believe you get a 30 day money-back
guarantee. I've used this before, and yes, they will take the server
back. The sales guys aren't too bright, they'll promise anything, but as
long as you can give the server back... (true, we buy a lot of dell
servers.. so... get confirmation from dell on what return policy applies
to your purchase)

If you're not concerned about space, go for the 8 2.5" disks. You'll get
more raw storage out of 300GB 3.5", but unless you need it, you'd be
better served with the additional spindles.

As for FreeBSD- I'd advise taking a good look at 6.2, its' in beta and
they've fixed quite a few problems with the 2950 (Raid controller and
bce nic issues come to mind). 

Lastly, if you have the money and rack space for an external disk cage,
take a look at Dell's MD1000 - not as good as some of the sun offerings,
but not too shabby for dell. (Note that I have not tested the MD1000 so
I'm just going off of my 2950 experience and the specs for the MD1000).

The above comes from being stuck with dell and trying to make the best
of it. Turns out it's not as bad as it used to be. Oh, and side note,
this may be obvious for some, but if you're running BSD and need
support, ask to speak to the Linux guys (or simply tell them you're
running Linux). Avoid Dell's windows support at all costs...

- Bucky



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