Field Notice: FN74238 - Cisco Secure Firepower Management Center Appliances: Disabled Write Cache Might Cause Slow GUI Response - Software Upgrade Recommended

The following Cisco Secure Firewall Management Center (FMC) appliances might have the write cache disabled, resulting in slow GUI response times:

• FMC1600
• FMC2600
• FMC4600

The Cisco FMC M5 appliances use hard disk drives (HDDs) to store event and log data. If the write cache is disabled on the FMC appliance, users might experience slow user interface response times during high disk I/O operations. This typically occurs during high event rates when host discovery is enabled and database processes are consuming high CPU and memory resources.

The Cisco FMC user interface will display slow response times, especially during high disk I/O operations.

To determine if the write cache is disabled, enter expert mode and run the storcli command:

> expert
admin@FMC$ sudo su -
Password:
Last login: Thu Mar 13 13:24:58 UTC 2025 on pts/0
root@FMC:/Volume/home/admin# storcli -LdInfo -Lall -aALL

Adapter 0 -- Virtual Drive Information:
Virtual Drive: 0 (Target Id: 0)
Name                :
RAID Level          : Primary-5, Secondary-0, RAID Level Qualifier-3
Size                : 1.633 TB
Physical Sector Size: 512
Logical Sector Size : 512
VD has Emulated PD  : No
Parity Size         : 557.861 GB
State               : Optimal <-- If "Degraded", contact Cisco TAC
Strip Size          : 64 KB
Number Of Drives    : 4
Span Depth          : 1
Creation Date     : 09-05-2024
Creation Time     : 07:13:27 AM>
Default Cache Policy: WriteThrough, ReadAheadNone, Direct, No Write Cache if Bad BBU
Current Cache Policy: WriteThrough, ReadAheadNone, Direct, No Write Cache if Bad BBU
Default Access Policy: Read/Write
Current Access Policy: Read/Write
Disk Cache Policy   : Disk's Default
Encryption Type     : None
Is VD Cached: No

The performance of the FMC device is affected when the write cache is disabled and any of the following conditions are true:

• The Default Cache Policy shows a status of WriteThrough and ReadAheadNone
• The Current Cache Policy shows a status of WriteThrough and ReadAheadNone
• The Disk Cache Policy shows a status of Disk's Default

Note: Confirm the state of the Cisco FMC hard drives. If the State shows Degraded (not Optimal), contact Cisco TAC to replace the affected hard drive(s).

To fix the issue that is described in this field notice, upgrade to a fixed software release. 

Workaround

Cisco recommends backing up the FMC configuration before performing the Workaround.

Enable the disk write caches to speed up the HDD I/O operations by entering expert mode and running the following storcli commands:

> expert
admin@FMC$ sudo su -
Password:
Last login: Thu Mar 13 13:24:58 UTC 2025 on pts/0
root@FMC:/Volume/home/admin# storcli /c0/v0 set wrcache=wb
root@FMC:/Volume/home/admin# storcli /c0/v0 set rdcache=ra
root@FMC:/Volume/home/admin# storcli /c0/v0 set pdcache=on

To verify that the write cache is enabled, enter expert mode and run the storcli command:

> expert
admin@FMC$ sudo su -
Password:
Last login: Thu Mar 13 13:24:58 UTC 2025 on pts/0
root@FMC:/Volume/home/admin# storcli -LdInfo -Lall -aALL

Adapter 0 -- Virtual Drive Information:
Virtual Drive: 0 (Target Id: 0)
Name                :
RAID Level          : Primary-5, Secondary-0, RAID Level Qualifier-3
Size                : 1.633 TB
Physical Sector Size: 512
Logical Sector Size : 512
VD has Emulated PD  : No
Parity Size         : 557.861 GB
State               : Optimal
Strip Size          : 64 KB
Number Of Drives    : 4
Span Depth          : 1
Creation Date     : 09-05-2024
Creation Time     : 07:13:27 AM
Default Cache Policy: WriteBack, ReadAhead, Direct, No Write Cache if Bad BBU
Current Cache Policy: WriteBack, ReadAhead, Direct, No Write Cache if Bad BBU
Default Access Policy: Read/Write
Current Access Policy: Read/Write
Disk Cache Policy   : Enabled
Encryption Type     : None
Is VD Cached: No

Optimal performance of the Cisco FMC device is achieved when the write cache is enabled and all of the following conditions are true:

• The Default Cache Policy shows a status of WriteBack and ReadAhead
• The Current Cache Policy shows a status of WriteBack and ReadAhead
• The Disk Cache Policy shows a status of Enabled

Note: The WriteBack and ReadAhead settings represent the RAID controller's write and read caches, respectively. The Disk Cache Policy represents the cache at each disk level. The write, read, and disk caches must be enabled to provide optimal performance of the Cisco FMC device.

Solution

To fix the Cisco FMC Software write cache issue, Cisco recommends upgrading to one of the Software releases shown in the following table:

Cisco offers a guided upgrade experience through the Secure Firewall Upgrade program. This program will provide environment-specific software upgrade guidance, a customized procedure to follow, and a customized pre-upgrade checklist. For additional information and to register for the upgrade program, see Get access to Cisco Secure Firewall LevelUp.