User's Manual

CacheCade Using Solid State Drives 277
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CacheCade Using Solid State
Drives
CacheCade is used to improve random read performance of the Hard Disk
Drive (HDD) 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 Dell 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 SSDs with the proper Dell identifiers can be used to create a
CacheCade.
• If you create a CacheCade using SSDs, the SSD properties are still
retained. At a later point of 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 can not be used as an additional
CacheCade or an SSD-based virtual disk.