There is a ram limit?

Hi:

There is a limit in the amount of ram I could use for mysql? (I have a
server with 96GB of ram)

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Re: There is a ram limit?

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This will mostly depend on your OS, really. Assuming you're running a 64-bit
flavour of *nix on that box, I don't think you have to worry.

On Fri, Jul 9, 2010 at 4:44 AM, Camilo Uribe wrote:

> Hi:
>
> There is a limit in the amount of ram I could use for mysql? (I have a
> server with 96GB of ram)
>
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> MySQL General Mailing List
> For list archives: http://lists.mysql.com/mysql
> To unsubscribe: http://lists.mysql.com/mysql?unsub=vegivamp@tuxera.be
>
>


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Re: There is a ram limit?

On Fri, Jul 9, 2010 at 12:03 AM, Johan De Meersman wro=
te:
> This will mostly depend on your OS, really. Assuming you're running a 64-=
bit
> flavour of *nix on that box, I don't think you have to worry.

Linux on 64-bits.

The default installation will use all the ram it needs or do I have to
configure something else?

> On Fri, Jul 9, 2010 at 4:44 AM, Camilo Uribe wro=
te:
>>
>> Hi:
>>
>> There is a limit in the amount of ram I could use for mysql? (I have a
>> server with 96GB of ram)
>>
>> --
>> MySQL General Mailing List
>> For list archives: http://lists.mysql.com/mysql
>> To unsubscribe: =A0 =A0http://lists.mysql.com/mysql?unsub=3Dvegivamp@tux=
era.be
>>
>
>
>
> --
> Bier met grenadyn
> Is als mosterd by den wyn
> Sy die't drinkt, is eene kwezel
> Hy die't drinkt, is ras een ezel
>

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Re: There is a ram limit?

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On Thu, Sep 23, 2010 at 12:39 AM, Camilo Uribe wrot=
e:

> On Fri, Jul 9, 2010 at 12:03 AM, Johan De Meersman
> wrote:
> > This will mostly depend on your OS, really. Assuming you're running a
> 64-bit
> > flavour of *nix on that box, I don't think you have to worry.
>
> Linux on 64-bits.
>

Yes, but is the Linux (and your MySQL) itself also 64-bits ? :-p You *can*
use all of your ram on a 32-bit linux with the Bigmem trick, but that
introduces quite a bit of overhead, and doesn't remove the per-process
limit. A 32-bit MySQL will simply not be able to address all that memory,
even on a 64-bit OS.



> The default installation will use all the ram it needs or do I have to
> configure something else?
>

The default setup will use all the RAM if it needs to - but it will do so b=
y
allocating per-connection buffers, the default shared pool sizes are rather
conservative.

For MyISAM you will need to tune query cache, key cache, read buffers, sort
buffers et cetera; for InnoDB you'll make a good start by allocating a larg=
e
chunk to the buffer pool. It may also (or may not, depending) be beneficial
to leave some ram for the OS' buffer cache, which caches filesystem blocks
and thus saves on raw reads.

More exact tuning pointers are best had by observing your database's
behaviour using a trending tool like Cacti or Munin. I've said it before an=
d
I'll say it again, my three favourite tuning resources are a) the online
docs, b) Baron & C°'s book High Performance MySQL and c) the Performance
Tuning course. With the number of parameters you can tweak on a MySQL, it's
hard to give more than basic tips without hand-on experience with the
system.



--=20
Bier met grenadyn
Is als mosterd by den wyn
Sy die't drinkt, is eene kwezel
Hy die't drinkt, is ras een ezel

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Re: There is a ram limit?

On Thu, Sep 23, 2010 at 1:21 AM, Johan De Meersman wro=
te:
> On Thu, Sep 23, 2010 at 12:39 AM, Camilo Uribe
> wrote:
>>
>> On Fri, Jul 9, 2010 at 12:03 AM, Johan De Meersman
>> wrote:
>> > This will mostly depend on your OS, really. Assuming you're running a
>> > 64-bit
>> > flavour of *nix on that box, I don't think you have to worry.
>>
>> Linux on 64-bits.
>
> Yes, but is the Linux (and your MySQL) itself also 64-bits ? :-p You *can=
*
> use all of your ram on a 32-bit linux with the Bigmem trick, but that
> introduces quite a bit of overhead, and doesn't remove the per-process
> limit. A 32-bit MySQL will simply not be able to address all that memory,
> even on a 64-bit OS.

Linux and MySQL of 64-bits:

uname -a
Linux blade2 2.6.18-164.el5 #1 SMP Thu Sep 3 03:28:30 EDT 2009 x86_64
x86_64 x86_64 GNU/Linux

file /usr/local/mysql/bin/mysqld
/usr/local/mysql/bin/mysqld: ELF 64-bit LSB executable, AMD x86-64,
version 1 (SYSV), for GNU/Linux 2.4.0, dynamically linked (uses shared
libs), for GNU/Linux 2.4.0, not stripped

>
>
>>
>> The default installation will use all the ram it needs or do I have to
>> configure something else?
>
> The default setup will use all the RAM if it needs to - but it will do so=
by
> allocating per-connection buffers, the default shared pool sizes are rath=
er
> conservative.
>
> For MyISAM you will need to tune query cache, key cache, read buffers, so=
rt
> buffers et cetera;

Thanks, I will look in High Performance MySQL and the mysql manual about th=
em.

By the way the server has all by default, so it use MyISAM.

> for InnoDB you'll make a good start by allocating a large
> chunk to the buffer pool. It may also (or may not, depending) be benefici=
al
> to leave some ram for the OS' buffer cache, which caches filesystem block=
s
> and thus saves on raw reads.
>
> More exact tuning pointers are best had by observing your database's
> behaviour using a trending tool like Cacti or Munin.

I'm going to install Better Cacti Templates
http://code.google.com/p/mysql-cacti-templates/

> I've said it before and
> I'll say it again, my three favourite tuning resources are a) the online
> docs,

The mysql manual?

> b) Baron & C°'s book High Performance MySQL

I'm reading it

> and c) the Performance
> Tuning course.

I didn't knew about this course, I will tell in my job about it and
see if they want to send me.

> With the number of parameters you can tweak on a MySQL, it's
> hard to give more than basic tips without hand-on experience with the
> system.

Thanks I'm going to look the things you said and come back later with
a little more of experiencie and precise questions

> --
> Bier met grenadyn
> Is als mosterd by den wyn
> Sy die't drinkt, is eene kwezel
> Hy die't drinkt, is ras een ezel
>

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