VxVM Vxmake

[Midrange]

Hi

I have just installed HP-UX 11.11 with the Veritas VxVM Volume Manager, I have also installed the VxFS 3.5 software by means of the veritas install script. I have one minor problem when creating volumes I am losing about 6.5 % of the volume size somewhere!

EG :-
/dev/vx/dsk/ofa_dev_dg/ofa_dev_cs
33003540 24556 30917805 0% /home/data/ofa_dev/cs
/dev/vx/dsk/ofa_dev_dg/ofa_dev_cs_cap
11702110 19336 10952608 0% /home/data/ofa_dev/cs/cap
volturno:/home/data/ofa_dev/cs # bc
11702110-19336
11682774
11682774-10952608
730166
volturno:/home/data/ofa_dev/cs # bc
33003540-24556
32978984
32978984-30917805
2061179

This is the same for both bdf and df! does anyone have any ideas ?

[Pete Randall]

I would have to assume that this is volume manager overhead: the VxVM data structures necessary to keep track of where data is located. You see the same in LVM volumes, just not as much.


Pete

[Midrange]

Thanks for the info, however this seems an alarming overhead! we are actually talking about 2Tbytes of total storage I have not allocated 6.5% overhead for this!. Any other thoughts would be appreciated, I've even resorted to longing a call with Veritas on this one!

[Zinky]

How are you creating your VxFS (aka Online JFS) filesystems on top of your VxVM volumes?

On our environment similar to yours, we use:

mkfs -F vxfs -o bsize=8192,largefiles /dev/vx/rdsk/vxvmdgname/volname

And we only have less than .2% "overhead" on the filesystem.

Note: there is no capacity overhead on VxVM volumes as like any other volume manager - it merely assembles your storage objects into storage units.

[Midrange]

Thanks for your help, the newfs -b 8192 option reduces this overhead dramatically.

[Midrange]

The solution was to unmount the empty f/s and run newfs -F vxfs -b 8192 against the rdsk!

All now OK
 

 

[Zinky]

Kool.. now since you've been helped - can you please assign points?