GRML minimal linux not stable with PV command

I am using GRML minimal Linux distro with PV piping command of Debian. PV is not available by default in grml minimal but I have downloaded and installed it as deb package. Now it's working fine when I use it after I log into the grml, but if I use it in a script at startup it somewhat like hang in between the process. % information st开发者_运维问答ops updating after little time.

Like if we use it in following way:

dd if=/somepath | pv | dd of=/somepath

This command will hang after some time.