I have a problems that is becoming very annoying. When ever I transfer large files using cp, mv, rsync or dolphin the system will slow down to the point that it's unusable. It will sometime hang completely and not accept any input until the file is transferred. I have no clue what could be causing this problem but I know it shouldn't be happening.
I am using Fedora 15 (18.104.22.168-0.fc15.x86_64) with KDE 4.6. have a Phenom II 955 processor, 6 GB of system ram and the OS and swap file is on an 80 GB SSD. Copying files in the SSD doesn't cause any problem, but moving files between my other two large HDDs causes the extreme slow down. Using htop I can see that my system load jumps to between 3 and 4, but my RAM and CPU usage stays low during the transfer.
Here are two commands that take about 10 mins to run and make the system unusable while it's running. It usually transferring around 2-20GB worth of data during the transfers:
cp -a /media/data.1.5/backup/Minecraft/backups/* /media/data.0.5/backup/Minecraft/backups/
rsync -a /media/data.1.5/backup/ /media/data.0.5/backup/
/media/data.1.5/ is the mount point for a 1.5 TB internal SATA drive, and /media/data.0.5/ is the mount point for a 500 GB internal SATA drive.