I’ve decided to stick with my rackable systems box as my fileserver because it’s relatively quiet and “green”. I have two identical servers so all i had to do was pop 4x 1.5TB drives in the new one (the old one had 4x 750GB) and migrate the data! The old server is running FreeNAS 7.2 and I loaded FreeNAS 8 RC2 onto the new one (ZFS support).
I can briefly remember attempting the migration task in the past and finding it somewhat easier said than done!
First i tried from a windows box connecting to each server using samba simply dragging/dropping the files. The transfer goes from the old server to the windows box then back to the other server so I decided this was a no go (performance was pretty poor and the samba process on both servers seemed to be eating the CPU but at least i got a progress bar).
Now I decided if i want the transfer to go directly from server to server i’d need to SSH into one of them and initiate the transfer from there. I mounted the old server on the new (mkdir /mnt/oldnas | mount oldnas:/mnt/data /mnt/oldnas) and proceeded to copy a folder (cp -R /mnt/oldnas/test /mnt/data). Unfortunately I couldn’t tell how fast the transfer was going nor the progress it had made!
So googling suggested rsync (rsync –progress) which provided speed and progress- great! Or not… unfortunately performance was even worse than before, only this time rsync was eating the CPU!
Next google result… scp (scp /mnt/oldnas/test newnas:/mnt/data)- using both local paths doesn’t display progress so one path must be nfs. Poor performance again! You guessed it… scp eating CPU.
So… back to cp! This time i passed -v to get an update after every file completes (cp -R -n -v /mnt/oldnas/test /mnt/data). Excellent! Only 10% CPU utilization… but can i determine how fast the transfer is going without timing how long a file (or group of files) takes to transfer? After trying a bunch of useless commands i finally found systat -ifs which shows current network throughput and peak network throughput- perfect!
Another update shortly!
P.S. I found that: systat -ifs doesn’t work prior to FreeBSD 8 (not a problem for me as i think FreeNAS 8 RC2 is based on FreeBSD 8.2) but: netstat -Iem0 -w1 -h is mildy helpful if you are running FreeBSD < 8.