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Frontier

Member

From: Chios, Greece

Registered: 2012-11-14

Posts: 11

Website

[SOLVED] SSD caching on Intel RST

Hello,

A quick description of my system:

- ASUS Z87-PRO with Intel RST enabled (RAID mode on BIOS)
- 1 HDD with my Arch Linux Installation (/dev/sdc1 is ext4, /dev/sdc2 is swap)
- 1 HDD with Windows 8.1 installation (/dev/sdb1 is NTFS)
- 1 SSD (/dev/sda) split in two 56GB partitions: one of 56GB is used as a cache disk (created with Intel RST tool under Windows) for the Windows disk, one of 56GB created (by the Intel RST tool) as a simple Data partition.

I am trying to use the SSD data partition under Linux; the final objective is to use this SSD partition as a Linux cache disk (EnhancedIO) for /dev/sdc1.
The problem I am facing is accessing this partition under Arch. Tried both dmraid and mdadm solutions - as explained below - without success.
On Windows, Intel RST creates the data partition unformatted by default.
On Arch, using cfdisk /dev/sda does detect the SSD - the whole capacity - but not the unformatted partition. Even if the unformatted partition gets formatted by Windows (NTFS), it is impossible under Arch to change the partition type (i.e from NTFS to ext4) and format it: mkfs.ext4 reports that /dev/sda1 (the formatted by Windows partition) is used by the system. This behavior is experienced both under a running system and via archiso boot.

With dmraid, the data and cache partitions are 'seen' upon boot (mkinitcpio regenerated according to wiki) as /dev/mapper/isw_eabhdecfdb_Data and /dev/mapper/isw_eabhdecfdb_Cache; however, the Data partition cannot be mounted as rw neither by mount command or via fstab entry.

Any ideas what I might be doing wrong?
Thank you very much in advance.

Last edited by Frontier (2014-05-09 13:00:27)

Frontier

Member

From: Chios, Greece

Registered: 2012-11-14

Posts: 11

Website

Re: [SOLVED] SSD caching on Intel RST

The initial objective was reached by unlinking the SSD from Intel RST switching from RAID to AHCI mode.
The next step was to partition the SSD and used it with EnhanceIO to accelerate the system.

I have updated the EnhanceIO wiki page with instructions on how to enable rootfs acceleration and my system now boots directly to KDE in 4 seconds