file system blocksize

[Ivan Thoelen]

How can I check the file system blocksize for a vxfs filesystem?

df -g show me always 8192 file-system blocksize.
But total blocks is always 1/1000 of the total amount of space for that filesystem.
So I would say 1k blocks.

[MARTINACHE]

Hi,

fstyp -v /dev/vgXX/lvXXXX

look at f_bsize value

Regards,

Patrice.

[Vincenzo Restuccia]

fstyp -v /dev/vgXX/lvolx|grep -i f_bsize

[Stefan Farrelly]

This has been argued over before. There are a lot of different definitions on what block size means;

Basically, HP-UX only talks to disks at 512bytes as a block size via the drivers. HFS uses 512bytes.

JFS uses DEV_BSIZE (declared in /usr/include/sys/param.h) as 1k. However, at a lower level this is still talking to the disk as 512bytes as thats what the HP-UX drivers use. fstyp -v and newfs use a block size parameter which defaults to 8 * DEV_BSIZE (so 8k), but again, at a lower level it uses DEV_BSIZE, so 1k, and even lower down to the HP-UX driver only talks to the disks at 512bytes. So take your pick as to the block size.

[Frank Li]

I thinks it should be the "f_frsize" . This value can be changed by the command "newfs_vxfs" with the -b option .

And I am also confused with "f_bsize" with "f_frsize" , does "f_frsize" mean fragment size ? but the command " newfs -F vxfs -b 2048 /dev/vg00/lvol# " just change the f_frsize value ?


Frank.

[Frank Li]

How can we change the f_bsize ? Or it is determinted my the system ? with the -b option of newfs_vxfs command you can only change the f_frsize , that is the fragment size .

Frank.

[Patrick Wallek]

From TKB document #1100330242

PROBLEM

How can I determine the current block size for the vxfs and hfs file systems?

CONFIGURATION

Operating System - HP-UX
Subsystem - System Administration

RESOLUTION

To determine the current block size for the vxfs file system:

fstyp -v /dev/vg00/lvol#

For example:

# fstyp -v /dev/vg00/lvol1

f_bsize: 8192

Note: The f_bsize parameter reports the block size for the vxfs file system.

To determine the current block size for the hfs file system:

tunefs -v /dev/vg00/rlvol# | grep bsize

For example:

# tunefs -v /dev/vg00/rlvol4 | grep bsize

sbsize 2048 cgsize 2048 cgoffset 24 cgmask 0xfffffff8
bsize 8192 bshift 13 bmask 0xffffe000

Here is an example of how HFS and VxFS actually interpret these fields:

Field HFS Value for VxFS
---- --- --------------
f_bsize block size (8K) largest possible block size (8K)
f_frsize fragment size (1K) actual block size (usually 1K)

[Kandaswamy Natarajan]

#mkfs -F vxfs -m /dev/vg00/lvol4
will give this output
mkfs -F vxfs -o ninode=unlimited,bsize=1024,version=4,inosize=256,logsize=1024,nolargefiles /dev/vg00/lvol4 1048576
here bsize value is the block size in bytes.