Issue detected on host - File closed with a dirty buffer alarm reported in vCenter

Products

• VMware vSphere ESXi

Issue/Introduction

• Warning alarms are repeated in vCenter for multiple hosts about a file "closed with dirty buffer". 

• If you check the /var/run/log/hostd log on the host referenced in the alarm you see log messages about NFC (Network File Copy) errors which reference the filename in the alarm. The log messages would be similar to the following example:

Hostd[2099522]: [Originator@6876 sub=Libs opID=hsl-<ID>] [NFC INFO]NfcFileRawClose: Closing file /vmfs/volumes/<VOLUME UUID>/<DIRECTORY NAME>/<FILENAME>
Hostd[2099522]: [Originator@6876 sub=Libs opID=hsl-<ID>] [NFC ERROR]NfcFileRawClose: Close error.
Hostd[2099522]: [Originator@6876 sub=Libs opID=hsl-<ID>] [NFC INFO]NfcFileConcludeFileStats: session=D38E19A1B0 Local filename = '/vmfs/volumes/<VOLUME UUID>/<DIRECTORY NAME>/<FILENAME>'

• Further into the hostd log there is a log message that indicates that the NFC error is due to no free disk space being available on the volume/datastore:

Hostd[2099516]: [Originator@6876 sub=Libs opID=hsl-<ID>] [NFC INFO]Nfc sessionId = <SESSION ID>, maxMem = 8295, maxStreamingMem = 0
Hostd[2099516]: [Originator@6876 sub=Libs opID=hsl-<ID>] [NFC ERROR]NfcFssrvrSendResponse: Found an error in the nfc session: There is no disk space available (NFC_NO_DISKSPACE)

Environment

VMware vSphere ESX

Cause

• A dirty buffer refers to a memory segment holding modified data that has not yet been written to disk. When the datastore is full, NFC is unable to complete all necessary write operations to the datastore.

Resolution

• On the host use the following command to identify the volume/datastore which has no free space.

- esxcli storage filesystem list

• Delete or move data from that datastore to free up available space or consider increasing the size of the datastore.