Configuring SSD Cache Settings

  1. Go to Storage & Snapshots > Storage > Cache Acceleration.
  2. Click Manage and then select Settings.

    The Switch SSD Cache window opens.

  3. Select which volumes and LUNs can use the SSD cache.
    Important:

    For data safety, volumes and LUNs created on an external storage device cannot use the SSD cache if the cache type is Read-write.

  4. Click Next.
  5. Select a cache mode.

    Cache Mode

    Description

    Recommended Use Cases

    Random I/O

    Only small data blocks are added to the SSD cache. Larger blocks are accessed directly from regular storage.

    Virtualization, databases

    All I/O

    Small and large data blocks are added to the SSD cache. Both sequential and random I/O requests are accelerated.

    Video streaming, large file access operations
    Tip:

    An HDD RAID group may outperform a SSD RAID group for sequential I/O if the ratio of HDDs to SSDs is 3:1 or greater, and the HDD group has a RAID type of RAID 0, 5, 6, or 10. However, SSDs will always be faster for random I/O. If the NAS contains a RAID group of type RAID 0, 5, 6, or 10 that contains three times more disks than the SSD cache, you should select Random I/O.

  6. Optional: Configure bypass block size.

    This value determines the maximum size of the data blocks that are stored in the SSD cache. Selecting a larger size may improve the cache's hit rate but uses more cache space. The default value is 1 MB.

  7. Click Finish.
Parent topic: Cache Acceleration