IDS Forum

Re: Raw Partition Vs Cooked FileSystem

Posted By: Art Kagel
Date: Thursday, 11 September 2008, at 11:38 a.m.

In Response To: Raw Partition Vs Cooked FileSystem (G K)

The old rule of thumb was that RAW devices are ~15% faster than COOKED
devices which are in turn ~10% faster than filesystem files (also COOKED).
That makes RAW ~25% faster than COOKED filesystem files.

You do have IDS 11.1 so your IDS version supports Direct IO as does (IB)
RHEL 5.1, so if you enable Direct IO (DIRECT_IO set to 1 in the ONCONFIG
file) you reduce the overhead of COOKED filesystem chunks from 25% to about
5% which is something you can live with if the convenience of having your
chunks in filesystem space is a priority for you.

Personally I think that chunks in filesystem space are more exposed to
fumble fingering and naive system administrators, so I still prefer RAW.

FYI, you should also configure at least one and preferably three smallish
temp dbspaces for sorting and unlogged temp tables, especially if you can
put them onto a separate structure. Ditto for the logical and physical
logs. Remember that almost 50% of you write IO will be to the logical logs
and over 50% if you include the physical log IO, so moving that bandwidth
off to a separate set of spindles can be a big win if there is a significant
write component to your systems.

Art

On Thu, Sep 11, 2008 at 10:29 AM, G K <ganeshkumarr@hcl.in> wrote:

> Hi All,
>
> I have an IDS 11.1 running on a quad core processor with RHEL 5.1 and a
> hard
> disk capacity of 80 GB.
>
> My database details:
>
> Root dbspace - 2.5 GB
> Dbspace 1 - 2.5 GB [ this contains the database]
> Maximum database size can go up to 537 MB only.
> My application requires periodic backup.
>
> I have been trying to figure out which would be suit my application - Raw
> partition or Cooked File system.
>
> Kindly help me out in evaluating the same for my application in terms of
> performance and access and response times.
>
> thanks and regards,
> g k
>
>
>
> *******************************************************************************
> Forum Note: Use "Reply" to post a response in the discussion forum.
>
>

--
Art S. Kagel
Oninit (www.oninit.com)
IIUG Board of Directors (art@iiug.org)

Disclaimer: Please keep in mind that my own opinions are my own opinions and
do not reflect on my employer, Oninit, the IIUG, nor any other organization
with which I am associated either explicitly or implicitly. Neither do those
opinions reflect those of other individuals affiliated with any entity with
which I am affiliated nor those of the entities themselves.

Messages In This Thread

• Raw Partition Vs Cooked FileSystem
  G K -- Thursday, 11 September 2008, at 10:29 a.m.
  • RE: Raw Partition Vs Cooked FileSystem
    Lello, Nick -- Thursday, 11 September 2008, at 10:33 a.m.
  • Re: Raw Partition Vs Cooked FileSystem
    Fernando Nunes -- Thursday, 11 September 2008, at 10:35 a.m.
    • Re: Raw Partition Vs Cooked FileSystem
      Art Kagel -- Thursday, 11 September 2008, at 11:40 a.m.
      • Re: Raw Partition Vs Cooked FileSystem
        Jim Tranny -- Thursday, 11 September 2008, at 2:24 p.m.
        • Re: Raw Partition Vs Cooked FileSystem
          Fernando Nunes -- Thursday, 11 September 2008, at 2:47 p.m.
        • Re: Raw Partition Vs Cooked FileSystem
          Art Kagel -- Thursday, 11 September 2008, at 3:36 p.m.
  • Re: Raw Partition Vs Cooked FileSystem
    Art Kagel -- Thursday, 11 September 2008, at 11:38 a.m.

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