Administrator Guide

Managing a Fluid Cache Cluster Environment

Configuring Fluid Cache Volumes

A Fluid Cache volume extends a normal Storage Center volume to be contained across the cache devices

in a Fluid Cache cluster as well as permanently stored in the Storage Center volume.

Limitations for Fluid Cache Volumes

There are a number of considerations before utilizing a volume in a Fluid Cache cluster:

• Fluid Cache volumes cannot be expanded

• Fluid Cache volume Read and Write Cache options are not available

• Fluid Cache volumes cannot be the source or destination of Live Volumes

• Fluid Cache volumes cannot be the destination of a replication

• Fluid Cache volumes cannot be part of a synchronous replication or simulation

Mapping Volumes in Fluid Cache

In Enterprise Manager, volume mappings created for a server in a Fluid Cache cluster behave similar to

any other volume mappings. Volumes can be mapped either to an individual server, or to a server cluster

(a “subcluster”) within the Fluid Cache cluster.

If Fluid Cache is used with ESXi clusters, it is quicker to map to a subcluster than to each individual server.

Mapping Volume to Servers

Before mapping a volume to a server node, create a Fluid Cache cluster (see Creating a Fluid Cache

Cluster).

To map a volume to a server:

1. In the Storage view, expand Storage Centers if necessary, and then select the Storage Center that

contains the appropriate volume.

2. In the Storage tab, expand Volumes if necessary, and then locate the volume you want to map.

3. Right-click the volume and select Map Volume to Server.

4. In the Map Volume to Server window, select the server.

5. Click Next.

6. Select Enable Fluid Cache.

7. From the Host Cache Policy drop-down menu, select a cache mode:

• Write-back (default): In addition to caching reads, write-back mode allows the caching of written

data without waiting for the Compellent Array to acknowledge the write operation. Write-back

caching requires a cache device on two or more servers in the cluster.

• Write-through: Write-through mode forces writes to both the cache and the Compellent Array

simultaneously. Warm reads and read-after writes are accelerated but write operations are not.

Write-through caching requires only one cache device on one server in the cluster.

NOTE: The cache mode selected for a volume mapping cannot be changed. To select a

different cache mode, you must remove the mapping and create a new mapping. When you

create the new mapping, you can then select a different cache mode.

8. (Optional) Select the Keep cached data on the node that accessed the data option. Selecting this

option gives the best performance for warm reads from the cache for datasets that fit on the local