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I was using Windows OS before but now I am a Linux user. My laptop has come with 30 GB SSD drive which was used for cache (I guess!). This is what It says on specifications page of my laptop:

Hard Disk Drive 500 GB*4 (Serial ATA, 5400 rpm) + solid state drive for cache 32 GB*5

On Windows, I was using Intel Rapid Storage Technology and everything was happening automatically. As I am on Ubuntu (14.04) now I don't know what to do with that SSD. I can just see it under:

Gparted --> Devices --> /dev/sdb (29.82)

Is there a way to use this with Linux? Or It is just a waste.

Any help would be much appreciated!

Thank you!

PS: I have only Ubuntu 14.04 installed. No Dual-Boot.

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  • is there any data on the drive presently?
    – Kalamalka Kid
    Oct 12, 2016 at 7:57
  • It was used for cache. I don't think there is anything relevant!
    – ObiWan
    Oct 12, 2016 at 8:39
  • do you wish to use it as a cache or to simply use it for storage?
    – Kalamalka Kid
    Oct 12, 2016 at 8:41
  • I will be glad to use it as a cache. But I don't know about pros and (especially) cons of using SSD as a cache on Linux. If it is easy to use and in the case of hazard my data will be safe then I will use it for cache. Otherwise, storage would be fine.
    – ObiWan
    Oct 12, 2016 at 8:48
  • I've been using Linux for a year now. Since my background is non-cs I am not good at OS concepts and all.
    – ObiWan
    Oct 12, 2016 at 8:49

2 Answers 2

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There are a few possible solutions for using an SSD as a cache device in Linux (in the same way that Intel Rapid Storage Technology works).

The two leading methods are to use the logical volume management subsystem (LVM), or bcache.

I've had performance problems with LVM (but only on large volumes > 10TB), and a few stability problems with bcache (although all fixed with newer kernels).

That having been said I currently use bcache on a handful of machines (including 3 servers) and the performance increase is dramatic with some workloads.

Neither solution is very simple to setup unfortunately, and I'd advise using newer kernels - such as those supplied with Ubuntu 16.04 or even 16.10 - with either option.

This guide by Redhat-employee Richard Jones outlines the use of LVM and retrofitting it to some existing LVM installations.

A simpler solution (probably lower performance overall and possibly better reliability) would be to to put both your root filesystem (/) and swap on the SSD, with other data on the hard disk drive.

Unfortunately, whilst this is easy to do with a new install of Ubuntu via the installer, re-partitioning an existing system like this is also not a straightforward operation, but there are guides online to this (or you could always ask a new question here).

Whatever you do (use the SSD as a cache or "straight" storage) you should use fdisk or gdisk (or other partitioning tools like gparted) to remove any existing Intel RST partitions, and partition the drive.

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  • Thanks for the quick answer. I can't afford to re-install ubuntu. I will try with re-partitioning. One more thing: Instead of re-partitioning can we use it as a drive for storage? Is it advisable?
    – ObiWan
    Oct 12, 2016 at 8:44
  • Yes, you can just use it as a storage drive (and/or for swap, as described in my answer). If possible, use it to host files which are frequently accessed and/or with random access (such as database files, email etc.), bearing in mind the 30 gigabyte maximum size. It's also worth bearing in mind that you can upgrade Ubuntu 14.04 to 16.04 in-place, if you then want to try LVM caching.
    – Tim Small
    Oct 12, 2016 at 12:22
  • Just because of the size I'm reluctant to install my system on that drive. I will try with LVM caching. Thanks :) (PS: If possible, please share any resource to understand LVM caching.)
    – ObiWan
    Oct 12, 2016 at 17:01
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First you have to ensure your Windows is no longer using the 30GB cache device by decelerating it. Then using Intel's RST windows application you can delete the volume.

I had a 30GB mSata SSD on my laptop that was split between 19 GB Windows Cache and 12 GB Ubuntu Cache (using EnhanceIO) for a year or so and it worked very well. But there was extra work to manage the caching.

Since then I've upgraded the 30GB mSata SSD to 120GB, moved the 500GB HDD from drive bay 1 to drive bay 2 and installed a new 240 GB SSD into drive bay 1:

rick@dell:~$ lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sdd      8:48   0 186.3G  0 disk 
├─sdd2   8:50   0 178.9G  0 part /media/rick/S3A6550D005
├─sdd3   8:51   0     6G  0 part 
└─sdd1   8:49   0   1.5G  0 part 
sdb      8:16   0 465.8G  0 disk 
├─sdb2   8:18   0 257.4G  0 part 
├─sdb5   8:21   0 200.5G  0 part 
├─sdb3   8:19   0     1K  0 part 
├─sdb1   8:17   0   100M  0 part 
└─sdb6   8:22   0   7.9G  0 part 
sr0     11:0    1  1024M  0 rom  
sdc      8:32   0 119.2G  0 disk 
├─sdc2   8:34   0  78.1G  0 part /mnt/5824BF4E76D68BE2
├─sdc3   8:35   0  29.3G  0 part /
└─sdc4   8:36   0   7.8G  0 part [SWAP]
sda      8:0    0 223.6G  0 disk 
├─sda2   8:2    0   118G  0 part 
└─sda1   8:1    0   100M  0 part

The 120 GB mSata SSD in question is installed as sdc. Windows has 78 GB and Ubuntu 16.04 has 29 GB along with 8 GB Swap partition.

The entire Ubuntu operating system and /home directory is installed within the 29 GB partition and performance is really good, especially considering the fact it's only a SATA II (3 GB/s) channel, albeit with a SATA III mSata SSD.

After ensuring Windows is deactivated from using the cache all you need to do is boot with a live CD or USB. At the installation screen select "something else". Re-partition the mSata SSD using gparted for Ubuntu and install it there.

I'll expand this answer with more details dependent on comments seeking additional information / clarification.

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  • Well, Thanks for the answer I was looking for. I have only Ubuntu 14.04 installed and 30 GB SSD is just there I'm not using it in fact I don't know how to make it usable. So what you are suggesting is to reinstall my distro into that 30 GB SSD?
    – ObiWan
    Oct 12, 2016 at 12:23
  • @ShivkaranSingh Sorry for the very long delay in answering. Yes you can install the entire Ubuntu programs and your /home directory to the SSD. Grub will still boot off of /dev/sda but will point to the mSata SSD in the menu.
    – WinEunuuchs2Unix
    Jan 27, 2017 at 2:43
  • well thanks. I will try this and let you know if it works.
    – ObiWan
    Feb 1, 2017 at 5:48

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