difference between fs version 4 and fs version 6

[laiju.c.babu]

Hi Team,

Could you please tell me the differnces between fs version 4 and fs version 6

we are doing one data migration from old LV to new LV .  After moving the data  it seems that the data usage is high in new LV ( aroound 30MB) . When i checked the difference in these LVs it came to  know that in old LVs the fs version is 4 and for the new LVs the fs version is 6.0.  Is there any additional over head is coming for fs version 6

 fstyp -v /dev/vgs1a106f/rlvol53

vxfs

version 6 ===========================> this for new LV

fstyp -v /dev/vgs1a1044/rlvol7

vxfs

version 4 ===========================> this for the old LV

Could you please help me on this

Regards

[Duncan Edmonstone]

I woudn't normally expect too much difference in filesystem usage, but then I might argue that 30MB isn't that high (how big is the filesystem in total?, what figure are you using for the comparison? Also what did you use to migrate the data between filesystems - for example cp doesn't detect sparse files, so a file (such as an Oracle temp file which are often sparse) which appears to be 200MB in size might only consume 100MB of actual disk space, but when copied to a new filesystem using cp would consume 200MB.

So...

- first off check _all_ the other parameters are the same in terms of what you see in the fstyp -v output (pay particular attention to f_frsize)

- confirm what tool you used to migrate the data - can it handle sparse files?

- check if you have sparse files in the original data (compare output of ls -l and du -k for a file)

[laiju.c.babu]

Hi Duncan,

Thanks  for the reply.

Please find the below details ( I am trying to find out the fs  which have 30MB difference. please find below fs which have 400KB difference)

/dev/vgs1a106f/lvol53          4194304    4193000    1304       100%       /****1541 ====> this is the new  lvol

/dev/vgs1a1044/lvol7           4194304    4188536    5736       100%       /****1541 =====> this is the old lvol

Here we can see a difference of 400KB more usage  in new lvol

1) Please find the fstyp output below

For new lvol

==========

     [5]> fstyp -v /dev/vgs1a106f/rlvol53
vxfs
version: 6
f_bsize: 8192
f_frsize: 8192
f_blocks: 524288
f_bfree: 163
f_bavail: 162
f_files: 64
f_ffree: 32
f_favail: 32
f_fsid: 1081016373
f_basetype: vxfs
f_namemax: 254
f_magic: a501fcf5
f_featurebits: 0
f_flag: 16
f_fsindex: 9
f_fsize: 524288

================================

For Old Lvol:

==========

     [6]> fstyp -v /dev/vgs1a1044/rlvol7
vxfs
version: 4
f_bsize: 8192
f_frsize: 8192
f_blocks: 524288
f_bfree: 721
f_bavail: 716
f_files: 192
f_ffree: 160
f_favail: 160
f_fsid: 1078198279
f_basetype: vxfs
f_namemax: 254
f_magic: a501fcf5
f_featurebits: 0
f_flag: 16
f_fsindex: 9
f_size: 524288

================================

2) For copying we are using cpio.

3) Lvol size is 4GB

Regards

[Dennis Handly]

>Here we can see a difference of 400KB more usage  in new lvol

I see 4,464 KB but that is still trivial.

>2) For copying we are using cpio.

That probably doesn't handle sparse files.

[laiju.c.babu]

Hi,

Is this overhead in space usage is happened due to the fs version or because of the usage of cpio.

Regards

[Dennis Handly]

>Is this overhead in space usage is happened due to the fs version or because of the usage of cpio.

I'm not sure.  You would first have to find a sparse file:

http://h30499.www3.hp.com/t5/System-Administration/Find-sparse-file/m-p/3875418

http://www.unix.com/programming/37375-locate-holes-sparse-file-2.html

http://www.dedoimedo.com/computers/linux-cool-hacks-more.html