Watch status of running dd disc clone

[tulamidan]

Hello
I have started a dd clone

 dd if=/dev/raid5/raidp1 of=/dev/ad8

And it keeps running for quite a while now. And I'd like to estimate if the process is still working and how long it might take to finish.

Top suggests that all is still fine:

  PID USERNAME      THR PRI NICE   SIZE    RES STATE  C   TIME   WCPU COMMAND
 1923 root            1  -8    0  3128K   840K physrd 2  65:48 11.57% dd

where physrd and physwrt keep switching.

but

freenas:~# pkill -INFO -x dd
freenas:~# kill -INFO 1923

show absolutely nothing. Is there some other way to show the progress?

 

[Phishfry]

If you look at the manual for dd(1) you will see it has a status component.

status=value

dd if=/dev/raid5/raidp1 of=/dev/ad8 status=progress

 

[k.jacker]

You can at any time press ^t while dd is running in your terminal

 

[m0nkey_]

I like to use something called pv.

dd if=/dev/source | pv | dd of=/dev/destination

 

[Eric A. Borisch]

I like to use something called pv.

dd if=/dev/source | pv | dd of=/dev/destination

If you know how big the transfer is going to be, you can use pv -s 12345 to get completion % / estimated time remaining.

 

[CraigHB]

Good info, can't say how many times I've sat there wondering when a dd job was going to finish.

 

[tulamidan]

Thanks for your responses. Next time I will start a job I keep in mind to add the progress flag.
I have read that pv slows down the copy of the process, can anyone confirm?

 

[tingo]

dd(1) also supports the status= option like status=progress which might be helpful in some cases...

 

[moridin]

Not-so-useful remark: a default bs is 512 bytes, you should really use something bigger (1M?).

 

[tingo]

That is a useful reminder. I routinely use bs=4M when copying to usb memory sticks, for example.

 

[Eric A. Borisch]

Thanks for your responses. Next time I will start a job I keep in mind to add the progress flag.
I have read that pv slows down the copy of the process, can anyone confirm?

Unless you are doing a memory device to memory device copy, I would expect not. In some cases, having an elastic buffer between your input an output device can make it faster. (You can adjust the size of pv’s buffer, or use mbuffer which also serves that purpose.)

 

[badbrain]

Use GNU ddrescue. It's better than dd.