Re: Filesystem Block Size ? 1K or 4K or 8K ?

This link from HP should help 
(http://h71019.www7.hp.com/ERC/downloads/4AA1-9839ENW.pdf)...

Paraphrasing from this article...
Redo log file systemsCreate redo log file systems with a 1 KB block size; use 
the following mount options:
delaylog,nodatainlog,convosync=direct,mincache=direct
Archive log file systemsCreate archive log file systems witha 1 KB block size. 
Mount options vary depending on the particularversion of JFS, as explained 
below.

JFS 3.3 and 3.5, without the sparse file I/O patch

For JFS 3.3 and 3.5 without the sparse file I/O patch (11.11: PHKL_32355, 
11.23: PHKL_34179), use the following mount options:
delaylog,nodatainlog
Modify the /etc/vx/tunefstab file,changing the discovered_direct_iosz parameter 
for the archive filesystem to 2097152, which enhances performance when writing 
archivefiles.
Note: Archive files are sparse files, which perform better with buffered I/O
JFS 3.5, with the sparse file I/O patch
For JFS 3.5 with the sparse file I/O patch, use the following options to mount 
the archive directory for direct I/O:
delaylog,nodatainlog,convosync=direct,mincache=direct
JFS 4.1 on HP-UX 11.23 and 11.31
The sparse file I/O issue is hasbeen resolved in JFS 4.1. Use the following 
options to mount thearchive directory for direct I/O:
delaylog,nodatainlog,convosync=direct,mincache=direct
Oracle tablespace file systemsHP offers the following suggestions for creating 
Oracle tablespace file systems:

Using HP-UX buffer cache
Create file systems with an 8 KB block size; use the following mount options:
delaylog, nodatainlog
While using HP-UX buffer cache may providesome benefit through JFS read-ahead, 
it may be better to bypass buffercache in environments that are very 
I/O-intensive.
Bypassing HP-UX buffer cache
Direct I/O can be more efficientthan using buffer cache and provides some 
benefit in I/O-intensiveenvironments. Note, however, that it is critical to set 
the Oracledb_file_multiblock_read_count value to 32 to avoid multi-block 
I/Osbeing broken down into individual, single-block, physical reads 
(seeSequential I/O penalty with readv and Higher Oracle multi-block readcount 
values).
Create file systems with an 8 KB block size; use the following mount options:
delaylog,nodatainlog,convosync=direct,mincache=direct
Oracle 10g and 11g environments
In an Oracle 10g or 11genvironment, allow the value of the 
Oracledb_file_multiblock_read_count parameter to remain at default, 
whichresults in1 MB reads that have no impact on the Oracle Optimizer logic.
Use the following options to mount a file system and specify direct I/O:
delaylog,nodatainlog,convosync=direct,mincache=direct
Oracle binaries file systemsUse the following mount options:
delaylog,nodatainlog

Pretty much says it all. Any questions?

Hope this helps...
Tim Gorman
consultant - Evergreen Database Technologies, Inc.
P.O. Box 630791, Highlands Ranch CO 80163-0791
website = http://www.EvDBT.com/
email = Tim@xxxxxxxxx
mobile = +1-303-885-4526
fax = +1-303-484-3608
Yahoo IM = tim_evdbt


VIVEK_SHARMA wrote:Folks

We are in the processof Setting up DB Server for an OLTP Banking Application 
Benchchmark.

HP-UX B.11.31
system device blocksize(think this is the O.S. block size) = 1K
Base page size = 4K.
DB_block_size = 8K

Should the Filesystem(VXFS) Block Size be set to 1K, 4K or 8K? …Personally I 
think it should be 4 K (i.e. Equal to the Page-size)

Cheers & Thanks Vmuch

Vivek

P.S. Will provide anydata needed




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