topic Re: System Blocksize in Operating System - HP-UX

System Blocksize

Amiel Tutolo — Thu, 25 May 2000 13:36:15 GMT

We are running HP-UX 11.0 and I need to find out what the SYSTEM BLOCKSIZE is? I am new to the SysAdmin arena and this system was originally setup by consultants so I have no idea where to start looking. Thanks for everyones help.

Re: System Blocksize

Andy Monks — Thu, 25 May 2000 13:42:51 GMT

No idea what you mean with 'SYSTEM BLOCKSIZE'.

The memory uses 4K pages, and the filesystems use different blocksizes.

To find out on a filesystem by filesystem basis do :-

fstyp -v

Re: System Blocksize

Alan Riggs — Thu, 25 May 2000 17:05:43 GMT

One additional note: you do not say what information exactly you require or how you need to use it. Andy is absolutely correct in his information. However, there are some older utilities and programs that assume a block size of 512 bytes. This is reflected in the standard reports of df and du, for example. If you are running a tool that reports blocks, then make sure it is accurately recording the true blocksize.

Re: System Blocksize

Amiel Tutolo — Thu, 25 May 2000 17:19:17 GMT

The reason I am asking is that the Oracle DBA is soing some tuning and wants to match his DB Blksize to the system blksize. He is saying when he takes the number of blocks that is showing up in the directory listing ( using ll ) he comes up with a 512 block size. I used the command that Andy posted and this showed a f_bsize = 8192.

Re: System Blocksize

Richard Hubbell — Thu, 25 May 2000 19:43:26 GMT

Are you sure about that page size?
Where did you get that number from?

Re: System Blocksize

Steven Sim Kok Leong — Fri, 26 May 2000 02:36:45 GMT

Hi,

I believe you are referring to the filesystem block size.

For good I/O performance, there is indeed an Oracle recommendation requiring that the database block size should not be larger than the filesystem block size. As a rule of thumb, deciding on the database block size depends on your oracle database and oracle application, that is, how large are your tables and how large are the records.

Regards.

Steven Sim

Re: System Blocksize

CHRIS_ANORUO — Fri, 26 May 2000 10:02:13 GMT

Amiel

The block size to usew for oracle is 4K you can also run dmesg command to see the physical and logical page sizes.