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filesystem block size

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Valued Contributor

filesystem block size



what's the best way to detect the filesystem block size  ( HPUX 11.31 ) ?


I read those following info's :


Default Block Size for HPUX 11.31 PA -RISC

HP-UX: How to check hpux block size


I made a test and created a filesystem with block size "1024" below :


"df -g" shows "8192 file system block size" and "1024 fragment size"
"fstyp -v" shows the same with other output.

So the right information is "fragment size" and not "file system block size" ?






/usr/sbin/lvcreate -n test -L 512 /dev/vgtest

/usr/sbin/newfs -F vxfs -o largefiles -b 1024 /dev/vgtest/rtest

fstyp -v "/dev/vgtest/test"

mkdir /test

mount -F vxfs -o delaylog,largefiles  /dev/vgtest/test /test

df -g /test
/test                  (/dev/vgtest/test ) :
8192 file system block size              1024 fragment size
524288 total blocks                          506667 total free blocks
475008 allocated free blocks           126668 total i-nodes
126664 total free i-nodes              126664 allocated free i-nodes
1074790519 file system id                    vxfs file system type
0x10 flags                                              255 file system name length
/test file system specific string

fstyp -v "/dev/vgtest/test"
version: 7
f_bsize: 8192
f_frsize: 1024
f_blocks: 524288
f_bfree: 506667
f_bavail: 475001
f_files: 126696
f_ffree: 126664
f_favail: 126664
f_fsid: 1074790519
f_basetype: vxfs
f_namemax: 254
f_magic: a501fcf5
f_featurebits: 0
f_flag: 16
f_fsindex: 9
f_size: 524288

Bill Hassell
Honored Contributor

Re: filesystem block size

20 years ago, filesystem block sizes were particularly important, especially for old versions of database engines (using files, not raw) like Oracle. VxFS allocates space as extents and blocks are simply internal bookeeping, with no meaningful effect for typical filesystems and access methods. Here are a couple of references:

Bill Hassell, sysadmin
Valued Contributor

Re: filesystem block size



we try to use the input's of this white paper:

HP-UX VxFS mount options for Oracle Database environments


so there are recommendations with different block size .

i also don't know about filesystem block size managment, when a third party software like ORACLE store in other block sizes ? 

example : a oracle database is created with block size 16 KB and the maximum filesystem block size is 8 KB.

so you mean, this is never mind !


Also it is interested , when you try to find sparse files , you must know the ORACLE block size , when the filesystem block size is not the same block size of a ORACLE database :


detect sparse files



last question : how can i detect the filesystem block size ?

Valued Contributor

Re: filesystem block size



i found the solution :


Accepted Solution oracle and filesystem block size


here are my questions about size listed