AdvFS: "Large BMT extentCnt", "BMT pageCnt is decreasing"?

Hi!

I am running V5.1B-3 with all current ERPs installed on a GS1280.  I am using 
AdvFS.  All file domains were created with Version 4 AdvFS data structures.

sys_check v139 reports a "Large BMT extentCnt (861)" on one of my domains, 
"BMT pageCnt is decreasing" on another.  For details, see below.  

I have tried verify -f and defragment on the domain with 861 extents, but that 
has not changed the number of extents.  I found earlier postings refering to 
Tru64 V4.0 that suggested recreating the domain with -p and -x options to 
mkfdmn (or addvolume), but documentation states that these options are not 
applicable for domains with Version 4 AdvFS data structures.

I would therefore ask for you advice:

- Are the messages anything to worry about in terms of performance or data 
integrity? 

- If so, how can I reduce the number of extents?  Should I use the 
addvol/rmvol/addvol/rmvol cycle suggested in other postings to rebuild my 
domain in a "clean" fashion?  Will addvol then size the BMT properly 
automagially?

- Any other suggestions (I guess using single 400GB partitions isn't optimal 
for AdvFS, nor having users creating millions of 10-byte files ...)?

Thanks a lot in advance!
Hans E Plesser

Details:

sys_check v139 reports a large BMT extentCnt (861) on one of my domains. 
nvbmtpg reports:

==========================================================================
DOMAIN "nlh_domain"  VDI 1 (/dev/rdisk/dsk3c)  lbn 48   BMT page 0
--------------------------------------------------------------------------
There are 235266 pages in the BMT on this volume.
The BMT uses 861 extents (out of 897) in 29 mcells.

Assuming that any BMT pages with 28 free cells are entirely empty (see 
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=716675), 
I find that some 153000 pages in the BMT are empty.  showfile -x reveals that 
all but the first three extents have 128 pages and 2048 blocks.

The domain contains three filesets with altogether some 150000 directories 
with about 2 million files.  The data is stored on a single volume (an ADG 
RAID with 407GB capacity).  

On another domain, sys_check complains that the "BMT pageCnt is decreasing".  
Here nvbmtpg reports:

==========================================================================
DOMAIN "scratch_domain"  VDI 1 (/dev/rdisk/dsk4c)  lbn 48   BMT page 0
--------------------------------------------------------------------------
There are 46851 pages in the BMT on this volume.
The BMT uses 141 extents (out of 673) in 22 mcells.

Only som 481 pages appear to be empty.  showfile -x shows that most extents 
have just between 1 and 8 pages.  This domain contains a single fileset with 
about 1 million files.  Data is stored on a single volume (RAID0 with 271GB 
capacity).



-- 
Dr. Hans Ekkehard Plesser
Associate Professor
Dept. of Mathematical Sciences and Technology
Norwegian University of Life Sciences
Phone +47 6496 5467
Fax   +47 6496 5401
Home  http://arken.umb.no/~plesser