I have a VirtualBox image using VDI and flexible size. Right now the physical DVI file 94GB. The host is an Ubuntu server and the guest is a CentOS 6.4 with ext4 partition. The host is using a sata normal disk of 1TB.
Disk read speed is:
sudo hdparm -tT /dev/sda /dev/sda: Timing cached reads: 23330 MB in 2.00 seconds = 11679.09 MB/sec Timing buffered disk reads: 420 MB in 3.01 seconds = 139.49 MB/sec
Disk write speed:
sudo dd if=/dev/zero of=output bs=8k count=128k; sudo rm -f output 131072+0 records in 131072+0 records out 1073741824 bytes (1.1 GB) copied, 4.91353 s, 219 MB/s
So... I guess copying a 100GB should take much less. In fact, a simple
cp takes a lot less. In my example, it takes 30 minutes, compared to the 2 hours of
I know that clonehd also does a compact so that might be a big difference. Now..say that I want to compact only once explicitly and then just clone. Is there another faster alternative? I read somewhere that what I can do is a simple
cp and then change the UUID of the created cloned image. Has anyone did this? Is it safe? Since I am doing this for backups...I need the process to be safe.
Note that I already cleaned free space in guest Cent OS using
zerofree. But this is not the topic of this thread.
Actually, I would not have that much problem if I could run the
clonehd while still running the VM, but I read this is not possible/recommended since the cloned/copied vdi files could be corrupted if it was concurrently modified.
Thanks in advance,