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* higth performance write to disk
@ 2013-09-04 15:22 Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
2013-09-04 15:27 ` Re: higth performance write to disk Merlin Moncure <mmoncure@gmail.com>
0 siblings, 1 reply; 5+ messages in thread
From: Jeison Bedoya Delgado @ 2013-09-04 15:22 UTC (permalink / raw)
To: pgsql-performance
Hello, in order to improve the performance of my database included in
the solution SAN SSD disk on RAID 10, but I see that the performance of
the database is the same. whichpostgresql.conf parameters that I do
recommend to change for use writing more.
Thank you very much.
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* Re: higth performance write to disk
2013-09-04 15:22 higth performance write to disk Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
@ 2013-09-04 15:27 ` Merlin Moncure <mmoncure@gmail.com>
2013-09-04 18:52 ` Re: higth performance write to disk Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
0 siblings, 1 reply; 5+ messages in thread
From: Merlin Moncure @ 2013-09-04 15:27 UTC (permalink / raw)
To: Jeison Bedoya Delgado <jeisonb@audifarma.com.co>; +Cc: pgsql-performance
On Wed, Sep 4, 2013 at 10:22 AM, Jeison Bedoya Delgado
<jeisonb@audifarma.com.co> wrote:
> Hello, in order to improve the performance of my database included in the
> solution SAN SSD disk on RAID 10, but I see that the performance of the
> database is the same. whichpostgresql.conf parameters that I do recommend to
> change for use writing more.
Going to need some more detailed information. In particular,
transaction rates, hardware specifics, database version, definition of
'slow', etc etc etc.
merlin
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^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: higth performance write to disk
2013-09-04 15:22 higth performance write to disk Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
2013-09-04 15:27 ` Re: higth performance write to disk Merlin Moncure <mmoncure@gmail.com>
@ 2013-09-04 18:52 ` Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
2013-09-04 19:19 ` Re: higth performance write to disk Tomas Vondra <tv@fuzzy.cz>
0 siblings, 1 reply; 5+ messages in thread
From: Jeison Bedoya Delgado @ 2013-09-04 18:52 UTC (permalink / raw)
To: pgsql-performance
Hi merlin,
Thanks for your interest, I'm using version 9.2.2, I have a machine with
128GB RAM, 32 cores, and my BD weighs 400GB. When I say slow I meant
that while consultations take or failing a copy with pgdump, this taking
the same time before had 10K disks in raid 10 and now that I have SSDs
in Raid 10.
That behavior is normal, or you can improve writing and reading.
thank you very much
El 04/09/2013 10:27 a.m., Merlin Moncure escribió:
> On Wed, Sep 4, 2013 at 10:22 AM, Jeison Bedoya Delgado
> <jeisonb@audifarma.com.co> wrote:
>> Hello, in order to improve the performance of my database included in the
>> solution SAN SSD disk on RAID 10, but I see that the performance of the
>> database is the same. whichpostgresql.conf parameters that I do recommend to
>> change for use writing more.
> Going to need some more detailed information. In particular,
> transaction rates, hardware specifics, database version, definition of
> 'slow', etc etc etc.
>
> merlin
>
>
--
Atentamente,
JEISON BEDOYA DELGADO
ADM.Servidores y comunicaciones
AUDIFARMA S.A.
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^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: higth performance write to disk
2013-09-04 15:22 higth performance write to disk Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
2013-09-04 15:27 ` Re: higth performance write to disk Merlin Moncure <mmoncure@gmail.com>
2013-09-04 18:52 ` Re: higth performance write to disk Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
@ 2013-09-04 19:19 ` Tomas Vondra <tv@fuzzy.cz>
2013-09-04 19:39 ` Re: higth performance write to disk Merlin Moncure <mmoncure@gmail.com>
0 siblings, 1 reply; 5+ messages in thread
From: Tomas Vondra @ 2013-09-04 19:19 UTC (permalink / raw)
To: pgsql-performance
On 4.9.2013 20:52, Jeison Bedoya Delgado wrote:
> Hi merlin, Thanks for your interest, I'm using version 9.2.2, I have
> a machine with 128GB RAM, 32 cores, and my BD weighs 400GB. When I
> say slow I meant that while consultations take or failing a copy with
> pgdump, this taking the same time before had 10K disks in raid 10 and
> now that I have SSDs in Raid 10.
>
> That behavior is normal, or you can improve writing and reading.
SSDs are great random I/O, not that great for sequential I/O (better
than spinning drives, but you'll often run into other bottlenecks, for
example CPU).
I'd bet this is what you're seeing. pg_dump is a heavily sequential
workload (read the whole table from start to end, write a huge dump to
the disk). A good RAID array with 10k SAS drives can give you very good
performance (I'd say ~500MB/s reads and writes for 6 drives in RAID10).
I don't think the pg_dump will produce the data much faster.
Have you done any tests (e.g. using fio) to test the performance of the
two configurations? There might be some hw issue but if you have no
benchmarks it's difficult to judge.
Can you run the fio tests now? The code is here:
http://freecode.com/projects/fio
and there are even a basic example:
http://git.kernel.dk/?p=fio.git;a=blob_plain;f=examples/ssd-test.fio
And how exactly are you running the pg_dump? And collect some basic
stats next time it's running, for example a few samples from
vmstat 5
iostat -x -k 5
and watch top how much CPU it's using.
Tomas
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^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: higth performance write to disk
2013-09-04 15:22 higth performance write to disk Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
2013-09-04 15:27 ` Re: higth performance write to disk Merlin Moncure <mmoncure@gmail.com>
2013-09-04 18:52 ` Re: higth performance write to disk Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
2013-09-04 19:19 ` Re: higth performance write to disk Tomas Vondra <tv@fuzzy.cz>
@ 2013-09-04 19:39 ` Merlin Moncure <mmoncure@gmail.com>
0 siblings, 0 replies; 5+ messages in thread
From: Merlin Moncure @ 2013-09-04 19:39 UTC (permalink / raw)
To: Tomas Vondra <tv@fuzzy.cz>; +Cc: pgsql-performance
On Wed, Sep 4, 2013 at 2:19 PM, Tomas Vondra <tv@fuzzy.cz> wrote:
> On 4.9.2013 20:52, Jeison Bedoya Delgado wrote:
>> Hi merlin, Thanks for your interest, I'm using version 9.2.2, I have
>> a machine with 128GB RAM, 32 cores, and my BD weighs 400GB. When I
>> say slow I meant that while consultations take or failing a copy with
>> pgdump, this taking the same time before had 10K disks in raid 10 and
>> now that I have SSDs in Raid 10.
>>
>> That behavior is normal, or you can improve writing and reading.
>
> SSDs are great random I/O, not that great for sequential I/O (better
> than spinning drives, but you'll often run into other bottlenecks, for
> example CPU).
>
> I'd bet this is what you're seeing. pg_dump is a heavily sequential
> workload (read the whole table from start to end, write a huge dump to
> the disk). A good RAID array with 10k SAS drives can give you very good
> performance (I'd say ~500MB/s reads and writes for 6 drives in RAID10).
> I don't think the pg_dump will produce the data much faster.
>
> Have you done any tests (e.g. using fio) to test the performance of the
> two configurations? There might be some hw issue but if you have no
> benchmarks it's difficult to judge.
>
> Can you run the fio tests now? The code is here:
>
> http://freecode.com/projects/fio
>
> and there are even a basic example:
> http://git.kernel.dk/?p=fio.git;a=blob_plain;f=examples/ssd-test.fio
>
>
> And how exactly are you running the pg_dump? And collect some basic
> stats next time it's running, for example a few samples from
>
> vmstat 5
> iostat -x -k 5
>
> and watch top how much CPU it's using.
yeah. Also, some basic stats would be nice. For example how much data
is getting written out and how long is it taking? We need to
establish benchmark of 'slow'.
merlin
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2013-09-04 15:22 higth performance write to disk Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
2013-09-04 15:27 ` Merlin Moncure <mmoncure@gmail.com>
2013-09-04 18:52 ` Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
2013-09-04 19:19 ` Tomas Vondra <tv@fuzzy.cz>
2013-09-04 19:39 ` Merlin Moncure <mmoncure@gmail.com>
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