Dell EMC Server Administrator Storage Management 9.1

CacheCade Using Solid-State Drives

CacheCade is used to improve random read performance of the solid-state drive (SSD) based virtual disks. A solid-state drive (SSD) is a data storage device that uses solid-state memory to store persistent data. SSDs significantly increase the I/O performance (IOPS) and/or write speed in Mbps from a storage device. With storage controllers, you can create a CacheCade using SSDs. The CacheCade is then used for better performance of the storage I/O operations. Use either Serial Attached SCSI (SAS) SSDs or Serial Advanced Technology Attachment (SATA) SSDs to create a CacheCade.

Create a CacheCade with SSDs in the following scenarios:

  • Maximum application performance — Create a CacheCade using SSDs to achieve higher performance without wasted capacity.
  • Maximum application performance and higher capacity — Create a CacheCade using SSDs to balance the capacity of the CacheCade with high performance SSDs.
  • Higher capacity — If you do not have empty slots for additional HDDs, use SSDs and create a CacheCade. This reduces the number of HDDs required and increases application performance.

The CacheCade feature has the following restrictions:

  • Only certified SSDs can be used to create a CacheCade.
  • If you create a CacheCade using SSDs, the SSD properties are still retained. At a later time, you can use the SSD to create virtual disks.
  • A CacheCade can contain either SAS drives or SATA drives but not both.
  • Each SSD in the CacheCade does not have to be of the same size. The CacheCade size is automatically calculated as follows: CacheCade size =capacity of the smallest SSD * the number of SSDs. The unused portion of SSD is wasted and cannot be used as an additional CacheCade or an SSD-based virtual disk.
  • The total amount of cache pool with a CacheCade is 512GB. If you create a CacheCade which is greater than 512GB, the storage controller still uses only 512GB.
  • The CacheCade is supported only on PERC H710P, PERC H800, and PERC H810 controllers with 1GB NVRAM.
  • In a storage enclosure, the total number of logical devices including virtual disks and CacheCade(s) cannot exceed 64.

NOTE: In order to use CacheCade for the virtual disk, the Write and Read policy of the HDD-based virtual disk must be set to Write Back or Force Write Back and read policy must be set to Read Ahead.
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