$ameer,
A "vxfs" filesystem is a type of advanced filesystem with
significantly better I/O and management features than a regular
"ufs" filesystem. When using advanced filesystems, as I said in
my posting, the "O/S blocksize" is irrelevant, as from an I/O
operation perspective, it gets overridden by the filesystem
blocksize. In a ufs filesystem the filesystem blocksize and the
O/S blocksize can differ.
Hope that answers all of your questions,
Gaja.
- "Oak, Sameer" <soak_at_ziptone.com> wrote:
> What is "vxfs filesystem" ??
> Also What is relationship between filesystem blocksize & O/S
> blocksize??
> Can these two differ????
>
> $ameer
>
> -----Original Message-----
> Sent: Tuesday, July 11, 2000 5:46 PM
> To: Multiple recipients of list ORACLE-L
>
>
> Aldi,
>
> If you are running a "vxfs filesystem", the filesystem
> blocksize
> overrides the default O/S block size of 512 bytes, from the
> perspective of I/O operations to that "vxfs filesystem". It
> is
> probably 8k if you took the default values while configuring
> your vxfs filesystem.
>
> This means that your db_block_size should be atleast 8k, given
> the OLTP/Batch nature of your application. If you are using
> "Quick I/O", then you may even want to set db_block_size =
> vxfs
> filesystem blocksize to minimize overhead during mapping. If
> you are running a lot of batch jobs through the day, then you
> may even go to a 16K db_block_size. Just make sure that
> "block-level contention" parameters like FREELISTS, INITRANS
> etc. are configured appropriately.
>
> The term "operating system I/O size" refers to the "chunksize"
> that the O/S uses to perform an I/O operation. On most
> flavors
> of Unix it is 64K. I believe, in more recent versions of
> Solaris, this is configurable and can be set to 128K or 256K.
> This however should be set keeping in mind the limitations of
> your hardware. After configuring that, the degree of striping
> (stripewidth) that you deploy in your logical volumes and the
> values you set for init.ora parameters like
> db_file_multiblock_read_count and hash_multiblock_io_count
> should be aligned with the "O/S I/O size" or "chunksize".
>
> It is my understanding that you cannot change the "O/S
> blocksize" after you have created your filesystems, as it
> refers
> to the "blocking factor" within a filesystem. But if that can
> be changed, someone please let us know.
>
>
> Best Regards,
>
> Gaja.
>
> --- Aldi Barco <ipal_at_hotmail.com> wrote:
> > Hi list,
> >
> > Here is from Oracle Manual :
> > "The operating system I/O size should be equal to or greater
> > than the
> > database block size".
> >
> > And the benchmark said that greater O/S block size is better
> > than small O/S
> > block size.
> >
> > My db_block_size now is 8K, and O/S block size is 512 bytes.
> >
> > Should I increase the O/S block size for better performance
> ?
> > Have you had
> > the benchmark in your machine ?
> >
> > Oracle 805, Sun OS 2.6, SGA 2 Gb, vxfs and ufs, OLTP and
> Batch
> > application.
> >
> > Thanks for any suggestion.
> >
> > Aldi
> > Oracle DBA
> >
> >
> >
>
> > Get Your Private, Free E-mail from MSN Hotmail at
> > http://www.hotmail.com
> >
> > --
> > Author: Aldi Barco
> > INET: ipal_at_hotmail.com
>
>
> =====
> Gaja Krishna Vaidyanatha
> Director, I-O Management Products
> Quest Software Inc.
> (972)-304-1170
> gajav_at_yahoo.com
>
> "Opinions and views expressed are my own and not of Quest"
>
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> INET: gajav_at_yahoo.com
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> Author: Oak, Sameer
> INET: soak_at_ziptone.com
>
> Fat City Network Services -- (858) 538-5051 FAX: (858)
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> San Diego, California -- Public Internet access /
> Mailing Lists
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> To REMOVE yourself from this mailing list, send an E-Mail
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subscribing).
Gaja Krishna Vaidyanatha
Director, I-O Management Products
Quest Software Inc.
(972)-304-1170
gajav_at_yahoo.com
"Opinions and views expressed are my own and not of Quest"
Received on Wed Jul 12 2000 - 12:49:50 CDT
