SQL Server – Backup – Error – The specified network name is no longer available.)’ while attempting ‘FlushFileBuffers’

Background

Attempting SQL Server backup to our Network File Server, but failing with an error message stating “The operating system returned the error ’64(The specified network name is no longer available.)’ while attempting ‘FlushFileBuffers’“.

Error Message


The operating system returned the error '64(The specified network name is no longer available.)' while attempting 'FlushFileBuffers' on '\\labfileserver\sqlbackup\hrdb_backup_2015_08_18_161953_6973966.bak'.  BACKUP DATABASE is terminating abnormally.

Resolution

Coverage

The resolution is well covered on the Internet:

  1. SESSTIMEOUT
  2. Drivers

Increase Session Timeout

Visually we can easily change the registry using regedit, but let us use command line.

Query


REG QUERY HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters /s

Output:

LanmanWorkStationParametersRead

Explanation:

  1. We can see that SessTimeout is not listed
  2. And, as such we are using the default timeout of 45 seconds ( https://technet.microsoft.com/en-us/library/cc938292.aspx )

Write

REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters /v SessTimeout /t REG_DWORD /d 360 

Output:

LanmanWorkStationParametersWrite

Explanation:

  • Thanks goodness, we were successful

Re-read


REG QUERY HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters /v SessTimeout

Output:

LanmanWorkStationParametersRead

Explanation:

  • We got back 0x168
  • 0x signifies Hex, and so let us covert to Decimal.  0x168 is 360 decimal

Retry Backup

The next time we retried backup, we were successful.

I think the problem is due to the way SQL Server backups database.  It allocates a big chunk of sparse file to make sure that the needed storage is available and reserved.  It does a lot of work and then goes back and writes out the backup file in chunks.

My thinking is that this causes network timeouts.

Using Compression

Let us make sure that we are using SQL Server Backup Compression:

ServerBackupCompression

We checked the “Compress backup” setting.

And, that saved us some storage the next time we attempted a backup.

SQLBackupFiles

The initial backup was 263 MB and the new one is 185 MB.

We thus saved 30%.

Other Errors

The good thing about writing is that it forces one into a hole.  By it’s very nature, you almost have to check out more things out.  In our case, there are numerous errors being logged in the Event Viewer.

Event Viewer – System

  • Type => Warning
  • Source => MrxSmb
  • Event => 3019

EvertViewer-3019

Quick Explanation:

  1. Every minute, a few entries are being logged

It appears that the registry entry item that we just changed will be effectual in better understanding this error, as well.

This is based on a quick reading of:

MSDN Blogs > Microsoft Open Specifications Support Team Blog > CIFS and SMB Timeouts in Windows
http://blogs.msdn.com/b/openspecification/archive/2013/03/19/cifs-and-smb-timeouts-in-windows.aspx

Summary

Again, thanks goodness for the Internet.

I really thought it was just out of date drivers (disk and network) and was spending time seeking the latest files out over the Internet.

But, since the registry patch worked without us having to restart the MS SQL Server Instance nor the host, life is good!

References

Registry / Command Line

  1. Reg /query
    https://technet.microsoft.com/en-us/library/Cc742028.aspx
  2. Reg /add
    https://technet.microsoft.com/en-us/library/Cc742162.aspx

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s