56541: Acronis Backup: Mounting of a Windows Share Can Fail with "Device not ready" or "Input/output error"


You are using Acronis Virtual Appliance in order to back up virtual machines to a share configured on Windows server 2012. Backup or replication to this share fails constantly or sporadically with the error:
Device not ready

Input/output error (code: 5)

In related asamba logs on appliance you can find errors like:

[1434996483] b401: Mon Jun 22 20:08:03 2015
[675:909]: '/bin/asamba' 'mount' '' 'testSRV' 'Backup' '/tmp/.mnt_net_M0eAYw' 'test\admin' 'XXXXXXXX' NOSMBFS=1
[1434996483] [675:909]: init_mount_cifs reusing existing mount point /tmp/.mnt_net_o9rvs2 returns=0
[1434996483] [675:909]: init_mount_cifs: Cannot read /tmp/.mnt_net_M0eAYw, errno = 121
[1434996483] [675:909]: init_mount_cifs failed, errno = 121
[1434996483] [675:909]: exiting with code 1


Oct 9 23:02:03 (none) user.info asamba: b403: Fri Oct 9 23:02:03 2015 [3502:3537]: '/bin/asamba' 'mount' '' 'testSRV' 'X' '/tmp/.mnt_net_VNNDmT' 'test\admin' 'XXXXXXXXX' CODEPAGE=866
Oct 9 23:02:03 (none) user.info asamba: [3502:3537]: init_mount_cifs reusing existing mount point /tmp/.mnt_net_6ibQFv returns=0
Oct 9 23:02:03 (none) user.info asamba: [3502:3537]: init_mount_cifs: Cannot read /tmp/.mnt_net_VNNDmT, errno = 5
Oct 9 23:02:03 (none) user.info asamba: [3502:3537]: init_mount_cifs failed, errno = 5
Oct 9 23:02:03 (none) user.info asamba: [3502:3537]: exiting with code 5


The root cause of this issue is that mount.cifs operation cannot allocate memory mounting Windows share.


First of all, check the permissions on your shared folder. Right-click the folder and select Properties. Your Windows user must be allocated permissions on both the Security and the Sharing tabs.

Then open Windows registry (Windows + R -> regedit.exe) and set HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache to ‘1’. This key tells Windows to set aside enough system cache for sharing large files.

Then set HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\Size  to ‘3’. This value tells Windows to prioritize file sharing over reducing memory usage. You can read more about this key here.

Reboot (or just restart the “Server” service in services.msc). The problem should now be solved.

More information

Please contact Acronis Customer Central if you need assistance.



You are reporting a typo in the following text:
Simply click the "Send typo report" button to complete the report. You can also include a comment.
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
11 + 9 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.