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I have a setup with 2 HDDs (1TB), 2 SSDs (32GB and 120GB) and 16GB RAM, and I want to do the following:

  • Put the two HDDs in a RAID 1 for redundancy, and use that volume for the bulk of file-saving, media, apps, etc. Plan on mounting / here in order to have most of my system backed up.

  • Setup the 32GB SSD for swap, and most system-stuff that typically aren't written that much to, like for instance /boot or wathever files make sense to put here, tips appreciated.

  • 16GB RAM is typically more than I need, so I'm wondering about using some of it as a RAM-disk, and place /tmp (and /proc and other cahce-stuff as well?) and similar there to increase performance without wearing out my SSDs.

Problem is that I don't, at the moment, know all the tools needed for this well enough, and neither do I have a good enough overview of the file-system to identify and place everything where I should go according to how I want the setup to be like.

So in short, I want to know:

  1. Detailed technical descriptions and advice on how to do this. Links to tutorials or similar are fine too, provided they are relevant enough of course.

  2. Additional tips on which folders and files should go where.

  3. If it's possible to somehow backup the files that would be placed on the SSD, outside of the RAID, to the RAID for total security in regards to data-loss? (Don't want to loose the boot-loader of course).

Ps: If some of you wonder about the 120GB SSD, I'm planning on using that for some games and some other programs where I need quick access-times to disk, not just RAM. But I might consider moving some of the files planned for the 32GB SSD there if it makes more sense.

I'm planning to use Ubuntu 13.10.

Thanks for any helpful answers :)

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Are you sure you want to use the plain hard drives for /? That doesn't make any sense to me as your daily experience with the speed of your OS will suffer. Please reconsider to put / on one of the SSDs as you only need about 10 GB for things like /usr, /lib and so on. Putting /boot on a SSD is really not useful at all and with 16GB of RAM you are really unlikely to use swap - consider turning it off or to use a small partition/LV on the hard drives. I'd say, avoid using the hard drives and use them only for a custom mount point, let's say /media/mybulkdata. –  gertvdijk Oct 20 '13 at 17:14
    
@gertvdijk This does makes sense. But I tend to store quite a lot of stuff, and I really would like to have most of my system backed up somehow, like in a RAID 1. That was my initial thought on placing / on the HDDs, and then explicitly move other frequently accessed data to SSD or RAM-disk. About the swap: Correct me if I'm wrong here, but doesn't some RAID-disk setups use swap as a buffer when synching with disk? –  Areyan Oct 20 '13 at 17:29
    
It still doesn't make any sense to me what you're trying to achieve here in the first place. 1) RAID is not a backup. I repeat. RAID is not a backup. 2) You appear to do the opposite of what you are trying to achieve. With / on plain spinning disks and SSD as swap you'll have a slow system in terms of daily usage. 3) SSD wearout is not an issue unless you're doing writes 24/7 to them. Really. Look for some literature on that. –  gertvdijk Oct 25 '13 at 0:09

1 Answer 1

Ubuntu used to provide this alternate install CD, which offered all md raid functionality during the partitioning step of the installer. I cannot find this online anymore, but I suspect you can give a try to the Ubuntu Server installlation CD. You can install the Ubuntu desktop even from the Server installation - it is really the same distribution, just with different default package selections.

Ubuntu used to employ the Debian System installer, which offers all the RAID features. The server Installation CD probably still does something similar, though I am not up to date on that.

Also I would recommend to use one of your SSDs as /-Partition and mount the Bulk-Storage to /home or /srv, depending on your use. Symlinking /home and /srv together is also not unheard of. The reason is that the operating system can really profit from the speedup offered by the SSD, so it would be a waste to put it on the disks. Also if your SSD breaks you can always just reinstall the OS, the safety offerd by the RAID1 is much more important for your own data.

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