Thread: How much ram is too much

How much ram is too much

From
Dave Cramer
Date:
Is it possible that providing 128G of ram is too much ? Will other
systems in the server bottleneck ?

Dave

Re: How much ram is too much

From
Guy Rouillier
Date:
Dave Cramer wrote:
> Is it possible that providing 128G of ram is too much ? Will other
> systems in the server bottleneck ?

What CPU and OS are you considering?

--
Guy Rouillier

Re: How much ram is too much

From
Ben
Date:
What is your expected data size and usage pattern? What are the other
components in the system?

On Fri, 8 Jun 2007, Dave Cramer wrote:

> Is it possible that providing 128G of ram is too much ? Will other systems in
> the server bottleneck ?
>
> Dave
>
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Re: How much ram is too much

From
Dave Cramer
Date:
It's an IBM x3850 using linux redhat 4.0


On 8-Jun-07, at 12:46 PM, Guy Rouillier wrote:

> Dave Cramer wrote:
>> Is it possible that providing 128G of ram is too much ? Will other
>> systems in the server bottleneck ?
>
> What CPU and OS are you considering?
>
> --
> Guy Rouillier
>
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Re: How much ram is too much

From
david@lang.hm
Date:
> On Fri, 8 Jun 2007, Dave Cramer wrote:
>
>>  Is it possible that providing 128G of ram is too much ? Will other systems
>>  in the server bottleneck ?

the only way 128G of ram would be too much is if your total database size
(including indexes) is smaller then this.

now it may not gain you as much of an advantage going from 64G to 128G as
it does going from 32G to 64G, but that depends on many variables as
others have been asking.

David Lang

[OT] Re: How much ram is too much

From
Zoltan Boszormenyi
Date:
Dave Cramer írta:
> It's an IBM x3850 using linux redhat 4.0

Isn't that a bit old? I have a RedHat 4.2 somewhere
that was bundled with Applixware 3. :-)

--
----------------------------------
Zoltán Böszörményi
Cybertec Geschwinde & Schönig GmbH
http://www.postgresql.at/


Re: How much ram is too much

From
"Joshua D. Drake"
Date:
david@lang.hm wrote:
>> On Fri, 8 Jun 2007, Dave Cramer wrote:
>>
>>>  Is it possible that providing 128G of ram is too much ? Will other
>>> systems
>>>  in the server bottleneck ?
>
> the only way 128G of ram would be too much is if your total database
> size (including indexes) is smaller then this.
>
> now it may not gain you as much of an advantage going from 64G to 128G
> as it does going from 32G to 64G, but that depends on many variables as
> others have been asking.

I don't know about the IBM but I know some of the HPs require slower ram
to actually get to 128G.

Joshua D. Drake


>
> David Lang
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Re: [OT] Re: How much ram is too much

From
"Joshua D. Drake"
Date:
Zoltan Boszormenyi wrote:
> Dave Cramer írta:
>> It's an IBM x3850 using linux redhat 4.0
>
> Isn't that a bit old? I have a RedHat 4.2 somewhere
> that was bundled with Applixware 3. :-)

He means redhat ES/AS 4 I assume.

J


>


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Re: [OT] Re: How much ram is too much

From
Dave Cramer
Date:
On 8-Jun-07, at 2:10 PM, Joshua D. Drake wrote:

> Zoltan Boszormenyi wrote:
>> Dave Cramer írta:
>>> It's an IBM x3850 using linux redhat 4.0
>> Isn't that a bit old? I have a RedHat 4.2 somewhere
>> that was bundled with Applixware 3. :-)
>
> He means redhat ES/AS 4 I assume.
>
Yes AS4
> J
>
>
>
>
> --
>
>       === The PostgreSQL Company: Command Prompt, Inc. ===
> Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
> Providing the most comprehensive  PostgreSQL solutions since 1997
>              http://www.commandprompt.com/
>
> Donate to the PostgreSQL Project: http://www.postgresql.org/about/
> donate
> PostgreSQL Replication: http://www.commandprompt.com/products/
>
>


Re: [OT] Re: How much ram is too much

From
Zoltan Boszormenyi
Date:
Joshua D. Drake írta:
> Zoltan Boszormenyi wrote:
>> Dave Cramer írta:
>>> It's an IBM x3850 using linux redhat 4.0
>>
>> Isn't that a bit old? I have a RedHat 4.2 somewhere
>> that was bundled with Applixware 3. :-)
>
> He means redhat ES/AS 4 I assume.
>
> J

I guessed that, hence the smiley.
But it's very unfortunate that version numbers
are reused - it can cause confusion.
There was a RH 4.0 already a long ago,
when the commercial and the community
version were the same. I think Microsoft
will avoid reusing its versions when year 2095 comes. :-)

--
----------------------------------
Zoltán Böszörményi
Cybertec Geschwinde & Schönig GmbH
http://www.postgresql.at/


Re: [OT] Re: How much ram is too much

From
mark@mark.mielke.cc
Date:
On Fri, Jun 08, 2007 at 08:54:39PM +0200, Zoltan Boszormenyi wrote:
> Joshua D. Drake írta:
> >Zoltan Boszormenyi wrote:
> >>Dave Cramer írta:
> >>>It's an IBM x3850 using linux redhat 4.0
> >>Isn't that a bit old? I have a RedHat 4.2 somewhere
> >>that was bundled with Applixware 3. :-)
> >He means redhat ES/AS 4 I assume.
> I guessed that, hence the smiley.
> But it's very unfortunate that version numbers
> are reused - it can cause confusion.
> There was a RH 4.0 already a long ago,
> when the commercial and the community
> version were the same. I think Microsoft
> will avoid reusing its versions when year 2095 comes. :-)

He should have written RHEL 4.0. RH 4.0 is long enough ago, though,
that I think few would assume it meant the much older release.

You'll find a similar thing with products like "CuteFTP 7.0" or
"CuteFTP Pro 3.0".

Cheers,
mark

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Re: [OT] Re: How much ram is too much

From
Zoltan Boszormenyi
Date:
mark@mark.mielke.cc írta:
> On Fri, Jun 08, 2007 at 08:54:39PM +0200, Zoltan Boszormenyi wrote:
>
>> Joshua D. Drake írta:
>>
>>> Zoltan Boszormenyi wrote:
>>>
>>>> Dave Cramer írta:
>>>>
>>>>> It's an IBM x3850 using linux redhat 4.0
>>>>>
>>>> Isn't that a bit old? I have a RedHat 4.2 somewhere
>>>> that was bundled with Applixware 3. :-)
>>>>
>>> He means redhat ES/AS 4 I assume.
>>>
>> I guessed that, hence the smiley.
>> But it's very unfortunate that version numbers
>> are reused - it can cause confusion.
>> There was a RH 4.0 already a long ago,
>> when the commercial and the community
>> version were the same. I think Microsoft
>> will avoid reusing its versions when year 2095 comes. :-)
>>
>
> He should have written RHEL 4.0. RH 4.0 is long enough ago, though,
> that I think few would assume it meant the much older release.
>

Yes. But up until RHEL 8.0/9.0 ( or plain 9 without decimals ;-) )
I can make cheap jokes telling that I can give you a free upgrade. :-)

> You'll find a similar thing with products like "CuteFTP 7.0" or
> "CuteFTP Pro 3.0".
>

I am sure there are others, too. But enough of this OT,
I am really interested in the main thread's topic.

Best regards,

--
----------------------------------
Zoltán Böszörményi
Cybertec Geschwinde & Schönig GmbH
http://www.postgresql.at/


Re: How much ram is too much

From
Guy Rouillier
Date:
Dave Cramer wrote:
> It's an IBM x3850 using linux redhat 4.0

I had to look that up, web site says it is a 4-processor, dual-core (so
8 cores) Intel Xeon system.  It also says "Up to 64GB DDR II ECC
memory", so are you sure you can even get 128 GB RAM?

If you could, I'd expect diminishing returns from the Xeon northbridge
memory access.  If you are willing to spend that kind of money on
memory, you'd be better off with Opteron or Sparc.

--
Guy Rouillier

Re: [OT] Re: How much ram is too much

From
Andreas Kostyrka
Date:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1



Zoltan Boszormenyi wrote:
> Joshua D. Drake írta:
>> Zoltan Boszormenyi wrote:
>>> Dave Cramer írta:
>>>> It's an IBM x3850 using linux redhat 4.0
>>>
>>> Isn't that a bit old? I have a RedHat 4.2 somewhere
>>> that was bundled with Applixware 3. :-)
>>
>> He means redhat ES/AS 4 I assume.
>>
>> J
>
> I guessed that, hence the smiley.
> But it's very unfortunate that version numbers
> are reused - it can cause confusion.
> There was a RH 4.0 already a long ago,
> when the commercial and the community
> version were the same. I think Microsoft
> will avoid reusing its versions when year 2095 comes. :-)

Well, RedHat Linux, and RedHat Linux Enterprise Server/Advanced Servers
are clearly different products :-P

And yes, I even owned Applix :)

Andreas

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Re: How much ram is too much

From
Dave Cramer
Date:
Actually this one is an opteron, so it looks like it's all good.

Dave
On 8-Jun-07, at 3:41 PM, Guy Rouillier wrote:

> Dave Cramer wrote:
>> It's an IBM x3850 using linux redhat 4.0
>
> I had to look that up, web site says it is a 4-processor, dual-core
> (so 8 cores) Intel Xeon system.  It also says "Up to 64GB DDR II
> ECC memory", so are you sure you can even get 128 GB RAM?
>
> If you could, I'd expect diminishing returns from the Xeon
> northbridge memory access.  If you are willing to spend that kind
> of money on memory, you'd be better off with Opteron or Sparc.
>
> --
> Guy Rouillier
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 3: Have you checked our extensive FAQ?
>
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Re: How much ram is too much

From
Jim Nasby
Date:
On Jun 8, 2007, at 11:31 AM, Dave Cramer wrote:
> Is it possible that providing 128G of ram is too much ? Will other
> systems in the server bottleneck ?

Providing to what? PostgreSQL? The OS? My bet is that you'll run into
issues with how shared_buffers are managed if you actually try and
set them to anything remotely close to 128GB.
--
Jim Nasby                                            jim@nasby.net
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)



Re: How much ram is too much

From
Dave Cramer
Date:
On 10-Jun-07, at 11:11 PM, Jim Nasby wrote:

> On Jun 8, 2007, at 11:31 AM, Dave Cramer wrote:
>> Is it possible that providing 128G of ram is too much ? Will other
>> systems in the server bottleneck ?
>
> Providing to what? PostgreSQL? The OS? My bet is that you'll run
> into issues with how shared_buffers are managed if you actually try
> and set them to anything remotely close to 128GB.

Well, we'd give 25% of it to postgres, and the rest to the OS.

What is it specifically you are referring to ?

Dave
> --
> Jim Nasby                                            jim@nasby.net
> EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)
>
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Re: How much ram is too much

From
Andrew Sullivan
Date:
On Mon, Jun 11, 2007 at 11:09:42AM -0400, Dave Cramer wrote:
> >and set them to anything remotely close to 128GB.
>
> Well, we'd give 25% of it to postgres, and the rest to the OS.

Are you quite sure that PostgreSQL's management of the buffers is
efficient with such a large one?  In the past, that wasn't the case
for relatively small buffers; with the replacement of single-pass
LRU, that has certainly changed, but I'd be surprised if anyone
tested a buffer as large as 32G.

A

--
Andrew Sullivan  | ajs@crankycanuck.ca
The whole tendency of modern prose is away from concreteness.
        --George Orwell

Re: How much ram is too much

From
Dave Cramer
Date:
Hi Andrew
On 11-Jun-07, at 11:34 AM, Andrew Sullivan wrote:

> On Mon, Jun 11, 2007 at 11:09:42AM -0400, Dave Cramer wrote:
>>> and set them to anything remotely close to 128GB.
>>
>> Well, we'd give 25% of it to postgres, and the rest to the OS.
>
> Are you quite sure that PostgreSQL's management of the buffers is
> efficient with such a large one?

No, I'm not sure of this.
> In the past, that wasn't the case
> for relatively small buffers; with the replacement of single-pass
> LRU, that has certainly changed, but I'd be surprised if anyone
> tested a buffer as large as 32G.

So does anyone have experience above 32G ?

Dave
>
> A
>
> -- Andrew Sullivan  | ajs@crankycanuck.ca
> The whole tendency of modern prose is away from concreteness.
>         --George Orwell
>
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Re: How much ram is too much

From
Dave Cramer
Date:
Hi Andrew
On 11-Jun-07, at 11:34 AM, Andrew Sullivan wrote:

> On Mon, Jun 11, 2007 at 11:09:42AM -0400, Dave Cramer wrote:
>>> and set them to anything remotely close to 128GB.
>>
>> Well, we'd give 25% of it to postgres, and the rest to the OS.
>
> Are you quite sure that PostgreSQL's management of the buffers is
> efficient with such a large one?

No, I'm not sure of this.
> In the past, that wasn't the case
> for relatively small buffers; with the replacement of single-pass
> LRU, that has certainly changed, but I'd be surprised if anyone
> tested a buffer as large as 32G.

So does anyone have experience above 32G ?

Dave
>
> A
>
> --
> Andrew Sullivan  | ajs@crankycanuck.ca
> The whole tendency of modern prose is away from concreteness.
>         --George Orwell
>
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> broadcast)---------------------------
> TIP 7: You can help support the PostgreSQL project by donating at
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