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Thread: Mapping tables to disk drives

Mapping tables to disk drives

From
Richard Emberson
Date:
Are there any guides, references, etc. for helping someone:
1) know how to map a particular table to a particular disk drive (is it
just symbolic links) and
2) for what type of queries and table layout combination would it make
sense to do so?

Thanks

Richard

Re: Mapping tables to disk drives

From
Bruce Momjian
Date:
Richard Emberson wrote:
> Are there any guides, references, etc. for helping someone:
> 1) know how to map a particular table to a particular disk drive (is it
> just symbolic links) and

Yep, just symlinks.  We know we need a better method.  Also, as the
table grows, extent files for >1gb will also need to be symlinked.


> 2) for what type of queries and table layout combination would it make
> sense to do so?

First, pg_xlog/ should be on a separate drive.  Then you can think about
moving indexes and tables to separate drives.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Re: Mapping tables to disk drives

From
Richard Emberson
Date:
Bruce Momjian wrote:

> Richard Emberson wrote:
> > Are there any guides, references, etc. for helping someone:
> > 1) know how to map a particular table to a particular disk drive (is it
> > just symbolic links) and
>
> Yep, just symlinks.  We know we need a better method.  Also, as the
> table grows, extent files for >1gb will also need to be symlinked.
>
> > 2) for what type of queries and table layout combination would it make
> > sense to do so?
>
> First, pg_xlog/ should be on a separate drive.  Then you can think about
> moving indexes and tables to separate drives.

I looked around the .../data directory. How does one map from index and
table names
to file names?

Also, I assume that when a extent file for >1Gb is created (by the DB as it
is running)
one must stop the DB, move the file, make a symbolic link to the moved file,
and then
restart the DB.

>
>
> --
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman@candle.pha.pa.us               |  (610) 853-3000
>   +  If your life is a hard drive,     |  830 Blythe Avenue
>   +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Re: Mapping tables to disk drives

From
Bruce Momjian
Date:
Richard Emberson wrote:
> Bruce Momjian wrote:
>
> > Richard Emberson wrote:
> > > Are there any guides, references, etc. for helping someone:
> > > 1) know how to map a particular table to a particular disk drive (is it
> > > just symbolic links) and
> >
> > Yep, just symlinks.  We know we need a better method.  Also, as the
> > table grows, extent files for >1gb will also need to be symlinked.
> >
> > > 2) for what type of queries and table layout combination would it make
> > > sense to do so?
> >
> > First, pg_xlog/ should be on a separate drive.  Then you can think about
> > moving indexes and tables to separate drives.
>
> I looked around the .../data directory. How does one map from index and
> table names
> to file names?

/contrib/oid2name.

> Also, I assume that when a extent file for >1Gb is created (by the DB as it
> is running)
> one must stop the DB, move the file, make a symbolic link to the moved file,
> and then
> restart the DB.

Yes, yuck.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026