[OpenIndiana-discuss] Snapshot destroy

[William David OpenIndiana]

I  have imported a pool from OS_b134 em upgraded to last version  but  on a try destroy a old snapshot my systems  hangs and  become a not responding  
after I execute  

zfs umount -f /dados/arquivos/documentos
zfs destroy /dados/arquivos/documentos at 20010530 (  435GB )

A I/O of zraid1 become a 134Kbytes/s and go a very slow for accessing anothers shares 
And I not concludes a destroy a snapshots  anyone have a advice ?

Tanks