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Recommended Patches for Direct NFS Client (Doc ID 1495104.1)

Last updated on OCTOBER 17, 2022

Applies to:

Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Oracle Database Cloud Service - Version N/A and later
Oracle Database - Enterprise Edition - Version and later
Information in this document applies to any platform.


This note lists the recommended patches for Direct NFS client for Oracle RDBMS Enterprise Edition 19c, 18c,,,, and

Also the below cumulative patches are available.

Note:  These  MLRs contain only Direct NFS fixes.   There will be other MLRs with additional non-Direct NFS fixes that can also be used. 

Direct NFS is an NFS client embedded in the Oracle database kernel and provides simplified administration and improved performance for NFS.

The list below is a list of known bug fixes for Direct NFS. These fixes are recommended for customers using Direct NFS client based on the configuration details described in the list below. Some of these bugs may also be applicable to older releases.


Bug Bug Description Configuration Impacted releases Bundle Patch Fix
32931941 This bug fixes a write corruption with dNFS enabled when dNFS has to retry writes due to NFSERR_DELAY or NFSERR_JUKEBOX. Generic 19.*
Patch: 32931941
This bug fixes open owner leaks with NFSv4/4.1. It also fixes a hang in the NFSv4 state renewal code seen when there is a network path failure. dNFS with NFSv4/4.1

 Patch: 32338919

Patch: 32806069

31178051 This bug fixes a database hang with NFSv4/ 4.1 when multiple network paths fail concurrently. dNFS with NFSv4/4.1
Patch: 31178051 
31745528 [3646736282511] kgnfs_check_rpc_frame: invalid RPC frame bp 0x7f603a836f88

Invalid RPC frame error accompanied with I/O errors and other file open errors when using NFSv4.

dNFS with NFSv4/4.1
Patch: 31745528 
32602599 Hang in recvmsg system call seen with Direct NFS enabled. Generic
Patch: 32602599 

ORA-600 [KSFDODM_CREATE1] while running RMAN backup with dNFS and NFSv4

dNFS with NFSv4/4.1

 Patch: 30381207

ORA-7445 [KGNFSGETMNTHDL()+3418] when using Direct NFS

This bug fixes an issue in Direct NFS where 64 byte NFS file handles were not being managed correctly by Direct NFS. This problem has been observed while running NFS backups to a Data Domain NFS server but could potentially happen with any NFS server.

Generic EXA BP

13043012 This bug fixes an issue that impacts Direct NFS multipath failover. Without this fix, Direct NFS may attempt a failover even if there is a single path to the NFS server. Although there are no noticeable performance regressions, it is advisable to apply this fix. Generic EXA BP


Improve Exadata RMAN backup performance to a ZFSSA.

Direct NFS is used to backup Exadata databases to a ZFS storage appliance. Direct NFS uses 1 MB send and receive buffers to issue 1 MB I/Os and this causes a performance degradation. The fix increases the buffer sizes to 4 MB to provide improved backup performance from an Exadata to a ZFSSA.

Exadata backup to ZFSSA EXA BP


Intermittent slow I/O if process is idle for over 5 minutes.

Each Oracle process creates its own connection to the NFS server. If the process is idle for over 5 minutes i.e. it does not issue any I/O for over 5 minutes, the NFS server cleans up the connection and the Oracle process has to reconnect when the next I/O is issued. This bug fixes an issue with the reconnect that caused the reconnect to take longer and increase the I/O latency.



Intermittent performance degradation with Direct NFS client.

Direct NFS retries I/Os with a very short timeout and under heavy I/O load the amount of retries can go up significantly leading to wasteful retransmissions and performance degradation. This bug increases the retry interval to eliminate the performance degradation. This bug can affect all configurations and may be accompanied with a PING timeout error in certain occurences.

Generic EXA BP 

Intermittent performance degradation with PING timeout messages and database hang symptoms.

Direct NFS: channel id 0 path **** to filer **** PING timeout.

This bug is caused by a spin in Direct NFS when the network and I/O load is very high and I/O latencies in excess of 5 seconds are seen. This issue is only seen in multipath environments.

If the NFS storage is NetApp, the following signature is observed in the messages file on the server.

Event 'nfsd.tcp.close.idle.notify' suppressed * times. Shutting down idle connection to client (***.***.***.***) where receive side flow control has been enabled. There are *** bytes in the receive buffer. This socket is being closed from the deferred queue.

Multipath environments EXA BP 

This bug is a Linux bug that affects Direct NFS configurations that do not use oranfstab. This bug affects 2.6.32 and 2.6.39 UEK Linux kernels and the bug is fixed in 2.6.32-300 and 2.6.39-200. Direct NFS users hitting this issue will see a database hang. Direct NFS is spinning in kgnfs_connect() -> skgnfs_bind() loop as the bind() call fails.

Workaround: A simple workaround for this issue is to configure oranfstab. The 'local' field should be specified in oranfstab and this will allow the bind() to succeed.

 Linux environment running 2.6.32 or 2.6.39 UEK kernel N/A N/A 

There is a small performance degradation for multiblock reads when using Direct NFS as Direct NFS fragments the reads into multiple single block reads. These reads are not fragmented if the OS NFS client is being used.

Generic EXA BP 

Hang observed in Direct NFS when running read intensive workloads. The hang call stack will contain one of the following functions.


Multipath environments EXA BP  

Slow I/O performance with Direct NFS and channel down error messages in the alert log. This bug is only seen in ZFSSA environments where Direct NFS and ZFSSA are communicating over an InfiniBand network. This does not impact standard Ethernet deployments. You will also see the following messages in the database alert log, /var/log/messages and the ZFSSA logs.

alert log - Direct NFS: channel id [0] path [] to filer ****** is DOWN

/var/log/messages - nfs: server ****** not responding, still trying"

ZFSSA logs - WARNING: High TCP connect timeout rate! System (port 2049) may be under a SYN flood attack.

REPLACED BY  Bug 17730745 - to track regression bug 17158897

Direct NFS connected to ZFSSA over InfiniBand

18061271 IPoIB connects can take a long time under load. During async reconnect, Direct NFS does not wait long enough to let the async connect complete leading to half open connects and triggers SYN flood protection on the ZFSSA. The fix allows more time for the async IPoIB connects to complete. Direct NFS connected to ZFSSA over InfiniBand EXA BP 
18191164 Slow read performance seen in Direct NFS connected to a ZFSSA over Infiniband network using IPoIB. If the ZFSSA enables SYN flood protection, the database does not get back any response from the ZFSSA. Without the fix, there is a spin in the kgnfs_complete_read() -> kgnfswat() code path that causes read performance degradation. Direct NFS connected to ZFSSA over InfiniBand EXA BP 

This bug addresses an intermittent ORA-7445 seen on database startup when using Direct NFS. The error is seen with the following signature:

ORA-07445: exception encountered: core dump [kgnfs_check_for_timedout_requests()+***] [SIGSEGV]

Generic EXA BP 

Wrong data returned for fragmented 4 MB RMAN reads in multipath environments with high I/O latency.

If the I/O latency is over 5 seconds, read fragments may be failed over to the other path and one can potentially hit this bug where wrong results are returned. The on-disk data is still correct and there is no on-disk data corruption.


Multipath environments EXA BP

Performance regression in RMAN backups and archival in if the storage is a ZFSSA

This regression is introduced in and the RMAN or archival throughput drops because the database is issuing synchronous writes to the ZFSSA.

Direct NFS connected to ZFSSA EXA BP  

Support management interface via oranfstab to issue SNMP queries to the storage.

Many storage administrators only enable SNMP over the management path. Previously, Direct NFS used to issue the SNMP checks over the data interface. With this fix, you can issue SNMP checks over the management interface.



Performance regression seen with certain workloads when running Direct NFS on Windows.

Direct NFS on Windows


Slow RMAN backup as copy performance from ASM to ZFS

This issue impacts the performance of RMAN backup as copy from an ASM or Exadata environment to an NFS backup location. The fix is in the RMAN layer but this is being tracked for Direct NFS since Direct NFS is the recommended backup method when backing up to NFS shares.

Exadata backup to NFS EXA BP DB BP


Long Direct NFS reconnect timeout when path comes back up after failover

When a Direct NFS path goes down due to failover, Direct NFS continues using the other available paths. It checks if the other path is back up periodically but has a long timeout since connects can block. Direct NFS now supports asynchronous connects so we are reducing this timeout to reconnect quickly.

Generic EXA DB BP


Support for non-default SNMP community string values

Certain users would like to use an SNMP community string other than the default value of 'public'. This patch lets users specify their own community string for Direct NFS to use when issuing the SNMP query to the storage server.






Errors seen in alter log on Windows databases when using Direct NFS

Windows Direct NFS was not handling directory creation correctly which is essential for FRA. This bug addresses this issue.

Direct NFS on Windows



High I/O latency reported by OEM when using Direct NFS

The high I/O latency was being reported due to a stale timestamp resulting in incorrect latency values being computed.





Crashes seen when Direct NFS is running with NFSv4 or NFSv4.1

This fix addresses various ORA-600/ ORA-7445 errors seen when Direct NFS is running with NFSv4 or NFSv4.1.




Crashes/ hangs seen in Direct NFS on truncated read completion

This fix addresses a Direct NFS bug when handling truncated read responses or partial reads due to end-of-file.




Crashes/ hangs seen in Direct NFS when IPv6 is being used

This fix addresses issues with parsing, bind and mount when IPv6 is being used.




ORA-600 [3020] seen on standby database with Direct NFS enabled

Under heavy database I/O load, Direct NFS may end up re-transmitting I/O requests including writes to the ZFSSA. There is a slight chance of an ordering issue between a new write and a previously re-transmitted write causing a lost write. The lost write is eventually detected and reported via the ORA-600 [3020] error.

Direct NFS connected to ZFSSA



Observed a database crash due to a write failure in DBW slave after enabling NFSv4.1 on Azure ANF storage.

This fix addresses database io error when enabling dnfs with nfsv4.1






IO Hang found during stress test -- Regression of 33132050









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