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 CacheCade Using Solid State Drives
Dell OpenManage Server Administrator Storage Management User's Guide
Manage CacheCade
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:
l Maximum application performance—Create a CacheCade using SSDs to achieve higher performance without wasted capacity.
l Maximum application performance and higher capacity—Create a CacheCade using SSDs to balance the capacity of the CacheCade with high
performance SSDs.
l 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:
l Only SSDs with the proper Dell identifiers can be used to create a CacheCade.
l 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.
l A CacheCade can contain either SAS drives or SATA drives but not both.
l 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.
l The total amount of cache pool with a CacheCade is 512 GB. If you create a CacheCade which is larger than 512 GB, the storage controller still uses
only 512 GB.
l The CacheCade is supported only on Dell PERC H700 and H800 controllers with 1 GB NVRAM and firmware version 7.2 or later.
l In a storage enclosure, the total number of logical devices including virtual disks and CacheCade(s) cannot exceed 64.
Manage CacheCade
Ensure that SSDs are available in the storage enclosure before performing any CacheCade operations. To create, resize, blink, or delete the CacheCade, go to
the CacheCade(s) screen:
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1. In the Dell OpenManage Server Administrator window, click Storage.
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2. Go to Storage Dashboard® Storage Controller® Available Tasks and select Manage CacheCade.
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3. Click Execute.
The CacheCade(s) screen is displayed.
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Creating a CacheCade
To create a CacheCade:
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1. In the CacheCade(s) screen, click Create CacheCade. The Create CacheCade screen is displayed.
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2. In the CacheCade Group section, select SATA SSD or SAS SSD if your system contains both SAS and SATA SSDs.
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3. Enter a name for the CacheCade. The size is calculated as follows:
CacheCade size = capacity of the smallest SSD * the number of SSDs
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4. From the available free disks that are displayed, select the SSDs that you would like to include in the CacheCade. The selected disks are displayed in the
Physical Disks Selected section.
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5. Click Finish.
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 or Adaptive Read Ahead.