User's Manual

Frequently Asked Questions

Question How do I contact Fluid Cache Technical Support?

Answer See Contacting Dell.

Question What is the lifecycle of my Dell Express Flash PCIe SSD?

Answer Dell warrants the Express Flash PCIe SSD to a maximum amount of data written to the PCIe

SSD in total bytes. The PCIe SSD monitors these cycles, and Dell software management

applications notify you when the warranty limits are reached. For more details, see the

Dell

PowerEdge Express Flash PCIe SSD User’s Guide

at dell.com/support/manuals.

Question How can I safely remove or replace a PCIe SSD?

Answer Use the fldc --remove command to notify Fluid Cache that you intend to remove a SSD. After

notification, you can physically remove a SSD from the system. See the topic “Removing

Working PCIe SSD From Cache Pool” in the section fldc CLI Commands.

Question How do I recover from removing the wrong PCIe SSD?

Answer Use the fldc --reactivate command to recover from a single PCIe SSD failure or removal. For

more information on a single PCIe SSD failure, see the topic “PCIe SSD Has Failed” in the

section Troubleshooting Fluid Cache For DAS.

Question What is the maximum cache size of Fluid Cache for DAS?

Answer The supported PCIe SSD capacities are 175 GB and 350 GB and you can install up to four PCIe

SSDs in your PowerEdge system. PCIe SSDs of the same capacities (either 175 GB or 350 GB)

can be combined to create flash cache capacity ranging from a minimum of 175 GB to a

maximum of 1400 GB.

NOTE: You cannot mix PCIe SSDs of different capacities for running Fluid Cache for DAS.

Question How does Fluid Cache for DAS ensure writes are not lost?

Answer In write-through cache mode, writes are sent both to the PCIe SSD and to the backing store.

This is slower than write-back cache mode, but it ensures that writes are not lost. In write-

back cache mode, writes are replicated across multiple PCIe SSDs and in the event of a PCIe

SSD or operating system failure, Fluid Cache for DAS can successfully recover the data.

Question What file system does Fluid Cache for DAS support?

Answer Any file system supported by the operating system(s) used by Fluid Cache for DAS is

supported. For more details on supported operating systems, see Software and Firmware

Prerequisites For Installing Fluid Cache.

Question What controls the cache flush rate?