I have OES2SP3 x64 (with the latest patches January 2013 Scheduled Maintenance for OES2SP3 (8404))

I enabled /ListXattrNWmetadata in nsscon and tried to move millions of files and dirs from volume1 to volume2 with this command rsync -aruAXp --stats --progess /media/nss/VOLUME1 /media/nss/VOLUME2
after several ours I noticed:

Max Thread Size : 50
Thread Peak Size : 50
Number of Queued Requests : 450
Queued Requests Peak Size : 450

So I increased max thread issuing this command ncpcon set CONCURRENT_ASYNC_REQUESTS=100

after several minutes values became

Max Thread Size : 100
Thread Peak Size : 98
Number of Queued Requests : 950
Queued Requests Peak Size : 950

then I did ncpcon set CONCURRENT_ASYNC_REQUESTS=200

and got

Max Thread Size : 200
Thread Peak Size : 198
Number of Queued Requests : 1000
Queued Requests Peak Size : 1000

after that sever didn't respond to rcndsd and ncpcon volumes and users were unable to map disks and login to that server