[PERFORM] Multiple data base on same server

2010-02-26 Thread elias ghanem
Hi,

I'm using postgresql 8.4

I need to install multiple postgresql dbs on one server but I have some
questions:

-Is there any problems (performance wise or other) if I have 10 to 15 DBs on
the same server?

-Each DB needs 10 tablespaces, so if I create 10 different tablespaces for
each DB I will have 100 to 150 table space on the same server. So can this
also cause any problems?

Thanks 



Re: [PERFORM] Multiple data base on same server

2010-02-26 Thread Richard Huxton

On 26/02/10 09:37, elias ghanem wrote:

Hi,

I'm using postgresql 8.4

I need to install multiple postgresql dbs on one server but I have some
questions:

-Is there any problems (performance wise or other) if I have 10 to 15 DBs on
the same server?


Clearly that's going to depend on what they're all doing and how big a 
server you have. There's no limitation in PostgreSQL that stops you though.



-Each DB needs 10 tablespaces, so if I create 10 different tablespaces for
each DB I will have 100 to 150 table space on the same server. So can this
also cause any problems?


Do you have 200-300+ disks to put these tablespaces on? If not, I'm not 
clear what you are trying to do. Why does each DB need 10 tablespaces?


--
  Richard Huxton
  Archonet Ltd

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Re: [PERFORM] Multiple data base on same server

2010-02-26 Thread Richard Huxton

On 26/02/10 12:45, elias ghanem wrote:

Hi,
Thanks for your answer,
Concerning the second point, each db have different table that are logically
related (for ex, tables for configuration, tables for business...) plus I'm
planning to put the indexes on their own tablespaces.
Concerning the disks I will maybe stored on multiple disks (but surely not
200-300). So I'm just wondering If this big number of tablespaces on a same
db server may cause problems,


If the tablespaces aren't on different disks, I'm not sure what the 
point is.


Do you perhaps mean schemas? So you have e.g. a system schema with 
tables users, activity_log etc? There's no problem with 20-30 
schemas per database.


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  Richard Huxton
  Archonet Ltd

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Re: [PERFORM] Multiple data base on same server

2010-02-26 Thread elias ghanem
Hi,
Thanks for your answer,
Concerning the second point, each db have different table that are logically
related (for ex, tables for configuration, tables for business...) plus I'm
planning to put the indexes on their own tablespaces.
Concerning the disks I will maybe stored on multiple disks (but surely not
200-300). So I'm just wondering If this big number of tablespaces on a same
db server may cause problems,
Thanks again.

-Original Message-
From: pgsql-performance-ow...@postgresql.org
[mailto:pgsql-performance-ow...@postgresql.org] On Behalf Of Richard Huxton
Sent: Friday, February 26, 2010 1:44 PM
To: elias ghanem
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Multiple data base on same server

On 26/02/10 09:37, elias ghanem wrote:
 Hi,

 I'm using postgresql 8.4

 I need to install multiple postgresql dbs on one server but I have some
 questions:

 -Is there any problems (performance wise or other) if I have 10 to 15 DBs
on
 the same server?

Clearly that's going to depend on what they're all doing and how big a 
server you have. There's no limitation in PostgreSQL that stops you though.

 -Each DB needs 10 tablespaces, so if I create 10 different tablespaces for
 each DB I will have 100 to 150 table space on the same server. So can this
 also cause any problems?

Do you have 200-300+ disks to put these tablespaces on? If not, I'm not 
clear what you are trying to do. Why does each DB need 10 tablespaces?

-- 
   Richard Huxton
   Archonet Ltd

-- 
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Re: [PERFORM] Multiple data base on same server

2010-02-26 Thread Craig James

Richard Huxton wrote:

On 26/02/10 12:45, elias ghanem wrote:

Hi,
Thanks for your answer,
Concerning the second point, each db have different table that are 
logically
related (for ex, tables for configuration, tables for business...) 
plus I'm

planning to put the indexes on their own tablespaces.
Concerning the disks I will maybe stored on multiple disks (but surely 
not
200-300). So I'm just wondering If this big number of tablespaces on a 
same

db server may cause problems,


If the tablespaces aren't on different disks, I'm not sure what the 
point is.


Our policy is that *every* database has its own tablespace.  It doesn't cost 
you anything, and it gives you great flexibility if you add new disks.  You can 
easily move an entire database, or a bunch of databases, by just moving the 
data pointing to the new location with symlinks.  Once you put a bunch of 
databases into a single tablespace, moving subsets of them becomes very 
difficult.

It also makes it really easy to find who is using resources.

We operate about 450 databases spread across several servers.  Postgres has no 
trouble at all managing hundreds of databases.

Craig

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Re: [PERFORM] Multiple data base on same server

2010-02-26 Thread elias ghanem
Ok thanks guys for your time

-Original Message-
From: Craig James [mailto:craig_ja...@emolecules.com] 
Sent: Friday, February 26, 2010 4:34 PM
To: Richard Huxton
Cc: elias ghanem; pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Multiple data base on same server

Richard Huxton wrote:
 On 26/02/10 12:45, elias ghanem wrote:
 Hi,
 Thanks for your answer,
 Concerning the second point, each db have different table that are 
 logically
 related (for ex, tables for configuration, tables for business...) 
 plus I'm
 planning to put the indexes on their own tablespaces.
 Concerning the disks I will maybe stored on multiple disks (but surely 
 not
 200-300). So I'm just wondering If this big number of tablespaces on a 
 same
 db server may cause problems,
 
 If the tablespaces aren't on different disks, I'm not sure what the 
 point is.

Our policy is that *every* database has its own tablespace.  It doesn't cost
you anything, and it gives you great flexibility if you add new disks.  You
can easily move an entire database, or a bunch of databases, by just moving
the data pointing to the new location with symlinks.  Once you put a bunch
of databases into a single tablespace, moving subsets of them becomes very
difficult.

It also makes it really easy to find who is using resources.

We operate about 450 databases spread across several servers.  Postgres has
no trouble at all managing hundreds of databases.

Craig

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Re: [PERFORM] Multiple data base on same server

2010-02-26 Thread Ing. Marcos Ortiz Valmaseda

elias ghanem escribió:


Hi,

I’m using postgresql 8.4

I need to install multiple postgresql dbs on one server but I have 
some questions:


-Is there any problems (performance wise or other) if I have 10 to 15 
DBs on the same server?


-Each DB needs 10 tablespaces, so if I create 10 different tablespaces 
for each DB I will have 100 to 150 table space on the same server. So 
can this also cause any problems?


Thanks

It´s depends of the features of the server. If is a good server, for 
example of 16 GB to 32 of RAM, with 8 a 16 processors, with a good SAN 
with RAID -1 for the pg_xlog directory and RAID-10 for the $PG_DATA 
using ZFS if you are using Solaris or FreeBSD and xfs or ext3 using 
Linux , on a Operating Systems of 64 bits, I think that this load can be 
supported.


There are installations of PostgreSQL with more than 400 db, but the 
environment is very distribuided on several servers.
About the tablespaces, It´s very necesary to have 10 tablespaces on each 
database? Normally, you can separate the table or the tables with more 
activity to a rapid disc array (I ´m thinking on a SSD array), other 
tablespace for the indexes if you have many, and for example with 
pl/proxy you could handle the partitions of your data.
There is not necessaty to have 100 or 150 tablespaces on the same 
server. You can separate this on a SAN, you can have two or more main 
PostgreSQL servers and several slaves with the data replicated on any 
case of data corruption on the main servers.
Rebember look the configuration of the performance of the PostgreSQL 
servers: work_mem, shared_buffers, etc

Regards and I hope that comments helps to you.


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