PV DD not copying data

[TheYikes]

hey! okay I'm back with yet another question. I'm trying to run

pv /home/yikes/Downloads/windows10/windows10.iso | dd of=/dev/sda1 bs=4M

the output on the konsole window says the data was copied successfully but when i look at the drive there's nothing on it.

[TheYikes]

OK i rebooted and it seems to be working fine now but I'm still not getting a real time feedback of the progress. At first it shoots up to 100% but them I'm left waiting for the process to complete.

[jlittle]

The problem is that Linux automatically uses any available free memory as a cache. If the iso size is less than the free memory, as is typical, all the iso is read into memory then pv and dd think the copy is finished.

I found an old USB 2 thumb drive and tried to reproduce the problem. I did, I think, at least once. Adding oflag=dsync to the dd command seemed to avoid it.

[TheYikes]

Thank you Jittle. I'll give it a go when I get home. I'll let you know how it goes on