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I have 120 GB SSD and 2TB HDD. Now I just wondering how to get best performance.

1st option is to install system on SSD and home to HDD. I have that in my laptop and works nice. But it take only 10% SSD into use and other does nothing.

2nd option seems to be to install bcache. In that manner complete SSD is used and even files on home can gain speed. But If I understand correctly for bcache I need 3 drives?!?

To clarify usage. I'm work with electronics so I do download a lot of datasheets and manuals, but not the movies. In my work I made changes in a lot of files and create / move / rename a lot of files. I do browse a lot, and have a lot of emails stored locally (thunderbird/firefox). I need reliable and safe system. With same hdd running over 6 years I don't have any issue. I'm affraid that sdd is not so secure.

So what is better option and does bcache really need 3 disks?

eSlavko
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2 Answers2

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1st option is to install system on SSD and home to HDD.

No I would not do that.

Use the SSD as the boot device and for /home. /home benefits from the SSD because all the configuration files are there.

Edit ~.config/user-dirs.dir to change the personal directories to you HDD and set all software, like browsers, to store downloads there. Video's and music do not benefit from an SSDs speed that much.

  • ssd: / 20Gb is enough for a desktop. More if you want to use servers. Or the whole 120 if you don't care about it (and not even make a seperate /home)
  • ssd: /home 5Gb is enough if you want it (you are not using it anyways and only need it for the configuration files). More than 10Gb can be overkill depending on usage.
  • hdd: /{mountpoint/} the whole 1Tb. When you reinstall you have it easy too: you format the ssd and mount the hdd.

You could leave the 95Gb on the ssd empty and use it for a 2nd, 3rd, 4th OS when you feel like installing more than 1.

Rinzwind
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You can probably enable Bcache with only one drive, but there wouldn't be any point. The Bcache homepage states:

Bcache is a Linux kernel block layer cache. It allows one or more fast disk drives such as flash-based solid state drives (SSDs) to act as a cache for one or more slower hard disk drives.

Based on this, it seems the requirements are "one or more... solid state drives" and "one or more slower hard disk drives". So the minimum number of drives needed are two.

If not dual booting:

  • EFI = 1-2GB on SSD. Why not smaller? It's a pain to deal with partitions that are too small. A couple GB won't be missed.
  • / = 32GB on SSD. Why not smaller, like 20GB? Smaller would have worked for 32-bit systems, but after the transition to 64-bits, I've had systems take up ~18GB for root. Dealing with partitions that are too small is a pain.
  • swap = RAM + 2GB on SSD. This is mainly for hibernation. If you'd rather use swap files, make / even larger.
  • bcache = 16-32GB on SSD? I don't know. It's up to you.
  • /home = Remainder of SSD. Why separate /home? User-specific settings are easier to preserve if the system has to be reinstalled.
  • /mnt/data = entire HDD. Then bind or symlink folders into home directory – Download, Pictures, Videos, etc.

If multi-booting:

  • Carve out space on the SSD for other operating systems. MS Windows needs 50-64GB to function. Updates won't work if there isn't enough space.
  • Maybe include 1-2GB /boot partition on SSD. This seems to be most useful if you intend to boot multiple Linux distros.
  • Format HDD in file system that can be used by all OSes, or make a transfer partition.

For VMs:

  • It may be possible to create a COW disk image on the SSD that is based on another disk image located on the HDD. The COW image acts as an intermediary that speeds up writes and some reads. This arrangement may improve the overall performance of the VM.
xiota
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