User's Manual

Configuring And Managing Fluid Cache For DAS

After Fluid Cache for DAS is installed and running, configure and manage your Fluid Cache environment. Fluid Cache for

DAS is configured at the command line using fldc commands or in Dell OpenManage Server Administrator.

NOTE: This document contains instructions for configuring and managing Fluid Cache for DAS using the fldc CLI

only. For information on configuring and managing Fluid Cache for DAS using OpenManage Server Administrator,

see the

Dell OpenManage User's Guide

at dell.com/support/manuals.

Configuring Fluid Cache For DAS Using fldc CLI

The fldc command line tool is located in the following directory: /opt/dell/fluidcache/bin

To review the available fldc commands, see fldc CLI Commands.

1. Add the first PCIe SSD cache device to the cache pool. Run the command: fldc --add --ssd=/dev/rssda

The following message is displayed: This operation will destroy all existing data

on /dev/rssda. Are you sure you want to proceed? [y=yes, n=no]

2. To confirm that you are adding the PCIe SSD cache device to the cache pool, type: y

The following message is displayed: SUCCESS: /dev/rssda added to fluid cache pool

3. Add the second PCIe SSD cache device to the cache pool. Run the command: fldc --add --ssd=/dev/

rssdb

The following message is displayed: This operation will destroy all existing data

on /dev/rssdb Are you sure you want to proceed? [y=yes, n=no].

4. To confirm that you are adding the second PCIe SSD cache device to the cache pool, type: y

The following message is displayed: SUCCESS: /dev/rssdb added to fluid cache pool.

5. Repeat step 3 and step 4 to add additional PCIe SSDs to a maximum of four SSDs.

6. Enable caching on one or multiple back end virtual disks in either of the two modes: write-back (WB) or write-

through (WT). Repeat either step a or step b below based on the type of mode you select for your back end virtual

disk(s).

Write-back mode In addition to reading cached data, WB mode allows the caching of writes. WB mode

requires the data to be written to a minimum of two PCIe SSDs. This mode also allows

applications to manipulate (read and write) large data sets in cache. Both reads and

writes are accelerated.

Write-through

mode

Use WT mode to force writes to both the cache and virtual back end disk simultaneously.

In this mode, reads are accelerated and writes are not accelerated. Under certain

conditions, system events can change the caching mode automatically to WT. For

example, if a replica block cannot be allocated, Fluid Cache changes modes from WB to

WT to ensure data protection.

a) For WB mode, run the command: fldc --enable -disk=/dev/sdb --mode=wb

The system displays the following message: SUCCESS: Caching enabled on Disk:/dev/sdb

Cache Mode:write-back Created Virtual Cache Disk:/dev/fldc0.