Hi
I've recently decided to upgrade my main PC, running Debian Jessie, to use SSDs instead of HDDs. Right now I am halfway through the process, having done what I consider the easy part, and about to start the potentially more difficult part.
The machine is a self-built circa 2009 machine with an Intel Core i7-920 processor, 24GB of RAM (originally built with 8GB and upgraded later) and 1.5TB of disk space originally spread over 2 HDDs -- 1 500GB disk which contained the whole filesystem except /opt with multiple partitions, and 1 1TB disk which is mounted on /opt.
The 1TB disk contains a mysql database instance, and also houses 2 Windows VirtualBox VMs for those few things I still need Windows for. It's also got a collection of videos and space for video transcoding work I do sometimes.
The migration was easy for the /opt disk -- just install the SSD, partition it, create an ext4 filesystem on it, mount it somewhere temporary, copy everything over from the /opt harddisk, and modify fstab so that it automounts the SSD going forward instead of the hard disk. I then rebooted to make certain I was fully over to the SSD. The 1TB HDD is still inside the machine but I plan to remove it when I open the box up again to add the second SSD. I'll set up periodic TRIM as a next step.
I've got a feeling though that the main disk is going to be a bit more of a challenge, and that is what I want advice about. I'm thinking I should boot from a live image and effect the copy there so that the disk is not mounted and in active use. Is that along the right lines or is there a better way?
The replacement SSD is 960GB where the original hard disk is 500GB. Would you recommend a dd if=/dev/sda of=/dev/sdd (or whatever it turns out to be), or a cp -r command like I used for the /opt disk, or some other way to execute the migration?
One complication is when I originally partitioned the 500GB disk I may have overdone it a bit. I've got separate partitions for /boot, /usr, /home, /tmp, /var, swap space and the root partition. I now consider that I overdid that and would ideally like to collapse /usr, /tmp and /var into the (correpondingly bigger) root partition, ie not have separate partitions for them and end up with root, /boot and /home (BIOS is too old for UEFI so using MBR booting so /boot partition makes sense). But, if trying to do so is going to make life significantly harder, I can accept not doing so -- but I do want to make full use of the available space on the new device so the partitions will not be the same size as they were.
What other things should I be concerned about (for example the discussion about ping using capabilities that was on this list a day or two back)? Oh, and speaking of MBR, as I was a paragraph ago, anything I should watch out for when trying to make the SSD bootable?
And anything else I should bear in mind when migrating to SSDs on a system that was originally installed on HDDs?
The HDDs are about 7 years old now -- the 500GB one has been in the machine since I built it, the 1TB is a replacement since its predecessor didn't enjoy the 2011 earthquake (I live in Tokyo, Japan) and failed shortly afterward. Hence my desire to migrate to newer hardware before they start failing again -- plus the speed and quiet advantages -- I figure with this upgrade plus adding a USB3 PCIe card I have a machine that's on par with any I could buy today.
The SSDs are recently-bought SanDisk Ultra II 960GB devices, Japanese model. I've already checked they have the latest firmware.