Default Block Size for HPUX 11.31 PA -RISC

[pamela gray]

Hi Experts,

I have a following situation:

I have HPUX 11.31 PA-RISC Foundation OE on hp rp3440 server. I have oracle 10.2.0.4 installed with all recommended patches for Oracle Database. I have RMAN doing backup along with Netbackup (on a different server) in nocatalog mode.

I need to know what is the default block size of above Operating System? RMAN uses default block size for backup and we need to improve backup performance. Hence was wondering if I can increase block size on hpux so that RMAN can access bigger block size. Also Oracle suggest to that we can supply block size while creating RMAN channel can what is the maximum channel block size I can use?

It' urgent so please respond quick.

Thanks in advance.

Regards,
Mitul Seth

[Tim Nelson]

man newfs_vxfs

-b block_size File system block size in bytes. The default value
is 1024 bytes for systems smaller than two
terabytes. For Version 5 disk layout file systems
larger than two terabytes, the maximum file system
size is dependent on the block size. A four
terabyte file system requires a 1K block size, An
eight terabyte file system requires a 2K block
size, a 16 TB file system requires a 4K block
size, and a 32 TB file system requires an 8K block
size.

[Steven E. Protter]

Shalom Mitul,

Maybe rman is different, but I've never been able to see a direct relationship between OS File System Block size and Oracle performance.

Set the rman block size as per the prior post, but don't expect performance to be great.

Suggestions:
Online JFS mirror split backups. You can basically cut an image of your file system, with a quick database bounce and then back up the image without impeding production or worrying about backup windows. It is a good cold backup.

Your storage solution may also provide answers to this issue.

SEP

[Ismail Azad]

Hi,

mkfs -F vxfs -o bsize... should allow you to change the block size.

Regards
Ismail Azad

[Johnson Punniyalingam]

How to check filesystem blocksize on HP-UX:
# fstyp -v | grep f_frsize)
(e.g. fstyp -v /dev/vg00/lvol3 | grep f_frsize)

How to create filesystems:

(For 8kb blocksize)
# newfs -F vxfs -b 8192 -o largefiles /dev//r

(For 4kb blocksize)
# newfs -F vxfs -b 4096 -o largefiles /dev//r

(For 1kb blocksize)
# newfs -F vxfs -b 1024 -o largefiles /dev//r

As far as I know, you can't change, the blocksize of a VxFS filesystem is set during creation ('mkfs_vxfs') using '-o bsize=n' where 'n' is a power-of-two between 1024 and 8192 inclusive. In order to change its value, I believe that you will have to backup the filesystem, recreate it and reload your data.


Regards,
Johnson