2 Replies Latest reply on Sep 28, 2016 2:14 PM by Intel Corporation

    Custom SSD cache volume size


      Hi guys,


      I am trying to accelerate one of my Intel RST RAID volumes with an Adata SP310 64GB SSD. My configuration is as follows:


      Asus H77M-Plus motherboard, Windows 7 Pro 64-bit, Intel RST drivers


      2 x Seagate 500GB HDDs (RAID0 volume)

      2 x Seagate 1000GB HDDs (RAID1 volume + RAID0 volume)

      Adata 64GB SSD


      I am trying to accelerate the RAID0 volume on the 500GB HDDs with the Adata SSD. However, I do not want to utilize the whole capacity of the SSD as a cache volume, because I want to provide some manual overprovisioning for the SSD (e.g. by allocating only 50GB for a RST cache volume and leave the rest of the SSD unused). The problem is that as far as I have 3 existing RAID volumes, Intel RST does not allow me to specify a custom cache volume size but forces me to use the whole SSD for the caching purposes. I suspect that this is because when only a part of the SSD is used for caching, RST automatically configures the rest of the SSD as a RAID0 data volume, thus the number of my RAID volumes would become 5 (while the maximum allowed number by Intel RST is 4).


      As a workaround I tried to detach temporarily the 1000GB HDDs (thus limiting the current number of RAID volumes to 1) and I then was able to specify custom cache volume size (50 GB). However, Intel RST configured automatically the rest of the SSD as a single-disk RAID0 volume (a data volume) and did not allow me to delete it (even through the BIOS utility). In this way I am not able to attach again the 1000GB HDDs (because the total number of my RAID volumes would become 5).


      My question is: How can I avoid creation of the "data volume" on the SSD (or how can I remove it after its creation) in order to decrease the number of my RAID volumes to 4?



        • 1. Re: Custom SSD cache volume size

          I found and implemented a low-level workaround. The trick was to create a Host Protected Area (HPA) on the SSD, thus reducing the drive size reported to and accessible by BIOS and OS. (First securely erased the SSD and then configured a HPA using the HDAT2 freeware utility). In this way both OS and BIOS see the SSD as a smaller one and they neither see nor use the allocated HPA. HPA remains "unused" and it will be used internally by the SSD's controller for over-provisioning purposes. In this way I did not have to specify custom IRST cache size (in order to provide manual over-provisioning) but allocated the whole disk as a cache volume. Over-provisioning is provided by the hidden unused HPA.

          • 2. Re: Custom SSD cache volume size
            Intel Corporation
            This message was posted on behalf of Intel Corporation

            Hello ddimitrov,

            Thank you for joining the Intel communities.

            I’m glad that you were able to solve this issue and thank you for taking your time to tell us how you solved it.
            Best wishes,