RE: OFF TOPIC : HP-UX OS BLOCK SIZe

Hi All,

No, the device block size under HP-UX is defined as 1024 bytes. See the #define for DEV_BSIZE in /usr/include/sys/param.h to verify. Many HP-UX utilities report 512-byte blocks merely for compatibility with other Unix flavours.

In any event, except its impact on the log block size, you should normally regard the term "O/S block size" as meaning the file system buffer size rather than the device block size. There is much more on this on my web site.

Regards,
Steve Adams

http://www.ixora.com.au/
http://www.oreilly.com/catalog/orinternals/
http://www.christianity.net.au/

-----Original Message-----
From: Christian Bilien [mailto:christian_at_open-seas.com] Sent: Friday, 4 August 2000 2:52
To: oracledba_at_quickdoc.co.uk
Subject: Re: OFF TOPIC : HP-UX OS BLOCK SIZe

Yes you are right, I went too fast when I first read the question (we are
on an Oracle list, so the FS block size has implications). The OS block size
as understood by du for example is indeed 512 bytes (compare bdf with du,
although some differences sometimes exist but nothing to do with the calculation). I do not see any practical use of this "OS block size" other
than changing the unit (blocks instead of bytes): I/O are performed in pages, file allocation in extents or FS blocks...

Christian Bilien
Performance consultant
christian_at_open-seas.com
www.open-seas.com

However, ----- Original Message -----
From: "Sherman, Edward" <shermanej_at_eccic.com> To: <oracledba_at_quickdoc.co.uk>
Sent: Thursday, August 03, 2000 4:57 PM
Subject: FW: OFF TOPIC : HP-UX OS BLOCK SIZe

> Please correct me if I am wrong but I think the bsize value shown is
the
> "file system" block size and not the "OS" block size. The file system
block
> size will be a multiple of the OS block size.
>
> The df -g command also shows file system block size
>
> The OS block size on most UNIX system is 512 bytes. I think this is
also
> true for HP-UX but I don't know how to prove it. :-(
>
> Running the df command by itself show the number of free 512-byte
blocks
> (according to the man page). I know this still doesn't prove the OS
block
> size if 512 bytes but seems to imply that it is (maybe).
>
> -----Original Message-----
> From: Christian Bilien [mailto:christian_at_open-seas.com]
> Sent: Thursday, August 03, 2000 10:11 AM
> To: Balasubramanian M
> Cc: oracledba_at_quickdoc.co.uk; ORACLE-L_at_fatcity.com
> Subject: Re: OFF TOPIC : HP-UX OS BLOCK SIZe
>
>
> Find out the character device used for this file system, then use
dumpfs
to
> get the the HFS options : bsize=block size, fsize= fragment size.
>
> **/dev/vg00/rlvol1:
> magic 95014 time Thu Aug 3 14:40:58 2000
> sblkno 16 cblkno 24 iblkno 32 dblkno 80
> sbsize 2048 cgsize 2048 cgoffset 24 cgmask 0xfffffff8
> ncg 35 size 86016 blocks 83733
> bsize 8192 shift 13 mask 0xffffe000
> fsize 1024 shift 10 mask 0xfffffc00
> frag 8 shift 3 fsbtodb 0
> minfree 10% maxbpg 77
> maxcontig 1 rotdelay 0ms rps 60
>
>
>
> HTH
>
> Christian Bilien
> Performance consultant
> christian_at_open-seas.com
> www.open-seas;com
>
> ----- Original Message -----
> From: "Balasubramanian M" <sbala_at_hclinsys.com>
> To: <ORACLE-L_at_fatcity.com>
> Cc: <oracledba_at_quickdoc.co.uk>
> Sent: Thursday, August 03, 2000 11:46 AM
> Subject: OFF TOPIC : HP-UX OS BLOCK SIZe
>
>
> >
> > Dear all,
> >
> > Please excuse me for putting the unix related things here.
Received on Thu Aug 03 2000 - 12:47:51 CDT