User's Manual

• A PCIe SSD is marked as failed.

Solution

• Cache status can degrade if you plug in only one PCIe SDD. You must have a minimum

of two PCIe SSDs to run Fluid Cache for DAS in WB mode. You can resolve the issue by

adding more PCIe SSDs to your system.

• Cache status can also degrade because a PCIe SSD has failed. To recover, follow the

steps below:

a. Check the status of the cache. Run the command: fldc --status

b. If the status indicates an SSD failure, see the topic “PCIe SSD Has Failed" in this

section.

Enabling Caching On Disk Has Failed

Probable Cause

• Disk mounting issue in /etc/fstab.

• The Fluid Cache virtual disk is unavailable.

• Evaluation license has expired after 90 days.

Solution

• To resolve the disk mounting issue, see the topic “Fluid Cache Disk Does Not Appear"

in this section.

• A Fluid Cache virtual disk might be unavailable for any of the following reasons:

– The Fluid Cache virtual disk is an unsupported device.

– The virtual disk is currently in use, either because it is already enabled as a

Fluid Cache disk, or it is in use by another application.

– The virtual disk does not exist. You cannot enable back end PERC virtual disks

that do not appear in the PERC card. For example, if you try to enable /dev/sdx,

and it does not exist, verify if it is displayed in the PERC card. To troubleshoot

the issue of the PERC card being unable to see the back end PERC virtual disk,

see the

Dell PowerEdge RAID Controller (PERC) User’s Guide

for the version of

PERC used in your system (H710, H710P or H810).

– If your PERC version is unsupported, you cannot see any back end PERC virtual

disks.

The solution for all of the above issues is the same. Use the fldc --list --disk command

to identify all the supported devices available for caching. Enable caching on a disk

that is both supported and available.

NOTE: Some Logical Volume Managers may pass every test as supported devices.

However, an LVM volume is not displayed in the fldc --list --disk output because

LVMs are not supported by Fluid Cache for DAS. Only supported devices can be

displayed in the fldc --list --disk output.

• Caching cannot be enabled on an existing Fluid Cache virtual disk if the Fluid Cache

license is missing or expired. Verify if your Fluid Cache license is valid. To verify your

license, run the command: fldc --status --license

Cannot Add Virtual Disk

Probable Cause Cannot add the 65th virtual disk to cache.