Putting / in the SSD and Swap and /home in the HDD seems reasonable.
/ will contain the OS, all the applications, and any server related stuff that does not belong to a specific user. For example, if you run a web server all the data files for the server will be in /.
So how big / should be depends on what you plan to do with the box. For "normal" desktop use 15-30GB should be more than enough. This should be sufficient for the OS and all the applications you may install in the future.
The advantage of keeping the OS and applications in the SSD is speed. However, personal settings and preferences are stored in the /home. So for the fastest results you may want to keep the /home in the SSD as well and use symbolic links to the folders with large data, such as Documents, Pictures, Music, Videos, etc. See Setup for dual disk (SSD+HDD) with /home partition for some details.
Hope this helps
The first question I'd be asking is Can the SSD be trusted as a primary drive? This was built to be a a cache drive and cache data is usually a copy of something stored elsewhere. There's no need for that data to have any integrity. Invalid data? Just rebuild off the main storage. To use it as primary storage might not be a great idea because corruption there is permanent.
Next, Does it perform well? Cache SSDs are cheap patches to plug the hole that is the incredibly slow magnetic disk that laptops get. If it's unbranded (and there are no specs on the internet), give it a quick spin with the Disk Utility in a Live CD/USB
If the answer to these two is anything but "it's fine, it's a solid disk", I'd look at replacing it with a better mSATA (I assume that's the connection but check first!) SSD. Even ~60GB ones aren't that expensive and you can be a little more assured that they're not going to die on their first outing as a primary disk.
Where you plop your partitions is largely going to depend on how you use your system. I don't know how much user content you have versus installed applications.
For what it's worth, with a 120GB SSD, I have / and /home on SSD with things symlinked and bind-mounted over to RAID5 and RAID1 and NFS. Steam allows you to store things on other media so that handles itself quite nicely. And I occasionally manually copy things to SSD for speed and symlink them.
... But I have the space to make that possible. 24GB is really restrictive. I don't think that approach is going to work well for you.
You're not mentioning another option: Throw the crappy 5400RPM laptop drive into the ocean and buy a better SSD to replace it and use network storage for all the data you hold dear.
Laptops are awful permanent storage because they get stolen, lost and dropped. It might make sense to have a centralised NFS NAS where you keep all the important stuff.
Best Answer
When you set up your Ubuntu installation, you mentioned that you placed the root directory (/) on the SSD, and the home directory (/home) on the HDD. This is a good start. I actually recommend placing root on your SSD, as well as home, and then create a directory such as
/mnt/datawhich is where you would put all of the data you wanted on your HDD. With this setup, I can easily symlink stuff on the HDD to my SSD, such as video games and movies, while keeping my system as fast as possible.I'm not quite sure why you want what you're asking for, as I'd personally want system stuff to be on the SSD to increase speed, while putting my less-important stuff on the HDD, however you can accomplish this much like how you set up your installation in the first place.
Instead of placing the home directory on the HDD, you could mount
/usr/binor even/usr. This is the typical place you'd findaptinstalling binaries.Before you take the time to do this, I'd highly recommend using
baobabor something like it to figure out 100% where you're losing space.If you'd like to separate both
/homeand/usr, you'd just have to split the HDD into two separate partitions.Other Ideas
As Barafu Albino added:
apt-get cleanregularly to remove unneeded packages and apt downloadsEdit
10GB is probably very small for a desktop computer. The only time I've seen something that small is when someone really breaks out all of the other mount points onto HDDs and stuff (maybe 20 ys ago) or on an embeded machine or something like a raspberry pi.