Blocksize on existing vxfs filesystem

[Kevin O'Donovan]

Hi,

I'm trying to find the blocksize of a filesystem I'm going to put a quota on (edquota looks for blocks rather than kbytes). I've come across a few commands to find this info:

# df -g /homes
/homes (/dev/vg05/lvol1 ) :
8192 file system block size 1024 fragment size
11780096 total blocks 67281 total free blocks
67281 allocated free blocks 135408 total i-nodes
20931 total free i-nodes 20931 allocated free i-nodes
1074069505 file system id vxfs file system type
0 flags 255 file system name length
/homes file system specific string
#

# fstyp -v /dev/vg05/lvol1
vxfs
version: 3
f_bsize: 8192
f_frsize: 1024
f_blocks: 11780096
f_bfree: 66857
f_bavail: 66857
f_files: 135408
f_ffree: 1073792296
f_favail: 1073792296
f_fsid: 1074069505
f_basetype: vxfs
f_namemax: 254
f_magic: a501fcf5
f_featurebits: 0
f_flag: 0
f_fsindex: 6
f_size: 11780096
#

# mkfs -F vxfs -m /dev/vg05/rlvol1
mkfs -F vxfs -o ninode=unlimited,bsize=1024,version=3,inosize=256,logsize=1024,nolargefiles /dev/vg05/rlvol1 11780096
#

The top 2 tell me that the blocksize is 8K, but the last one is talking about 1K. Anyone know whats going on with these, and which is correct?

thanks in advance, Kevin.

[Duncan Edmonstone]

I *can't* tell you whats going on!

But I can tell you that the block size on your file system is 1024 - This is reported as the gragment size on df and fstyp

HTH

Duncan

[Marcin Wicinski]

Hi,
df -g reports all information contained in statvfs structure:
f_bsize; /* preferred file system block size */
f_frsize; /* fundamental file system block size */

Later,

[Roger Baptiste · Accepted solution]

Kevin,

I ran into this same issue few months back.
Even though df
***
# df -g /homes
8192 file system block size
1024 fragment size
version: 3
f_bsize: 8192
f_frsize: 1024
**

The frsize (or fragment size) is infact the actuall block size of the filesystem and it is the default Block size used by the newfs/mkfs commands. So, if you need a higher block size (as is the norm especially on oracle db), use the -b option with the newfs command to specify the new block size. Pls note , you cannot change the block size of existing FS.

HTH
raj

[Sanjay_6]

Hi Kevin,

The command " fstyp -v /dev/vg05/lvol1" is reporting the correct block size "f_bsize: 8192".

Take a look at the thread below,

http://us-support2.external.hp.com/cki/bin/doc.pl/sid=754ce4000419e32a95/screen=ckiDisplayDocument?docId=200000054230626

Hope this helps.

Regds

[Duncan Edmonstone]

Sorry Sanjay, I just checked that thread, and if you look at the last few lines, they spell out the truth:
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)


So f_bsize is the maximum possible block size you can have on a vxfs file system, which is born out by the following example:

# newfs -F vxfs -b 16384 /dev/vg00/rlvol25
vxfs mkfs: bsize must be a power of 2 >= 1024 and <= 8192

And f_frsize is the actual block size for vxfs file systems as in:

# newfs -F vxfs -b 4096 /dev/vg00/rlvol25
version 3 layout
106496 sectors, 26624 blocks of size 4096, log size 512 blocks
unlimited inodes, 26624 data blocks, 26080 free data blocks
1 allocation units of 32768 blocks, 32768 data blocks
last allocation unit has 26624 data blocks
first allocation unit starts at block 0
overhead per allocation unit is 0 blocks
# fstyp -v /dev/vg00/lvol25
vxfs
version: 3
f_bsize: 8192
f_frsize: 4096
f_blocks: 26624
f_bfree: 26075
f_bavail: 25668
f_files: 6544
f_ffree: 6512
f_favail: 6512
f_fsid: 1073741841
f_basetype: vxfs
f_namemax: 254
f_magic: a501fcf5
f_featurebits: 0
f_flag: 0
f_fsindex: 6
f_size: 26624

HTH

Duncan

[Kevin O'Donovan]

Thanks lots for the replies!

Bit of a confusing one so a quick summary, it means different things for HFS & VXFS filesystems. The document Sanjay points to (thanks) doesn't clarify it very clearly until the end where it has:
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)

So Duncan, Marcin and particular Rajman were right on the button. thanks!! Kevin.