CIFS failed to allocate memory?

If you are mounting your Windows network shares in your Ubuntu, do not hurry to move your files to this newly added mount point. Most probably you will be regret very soon, as the system may give you error Failed to allocate memory and soon after that your files will gone missing. Yes, all gone! That's what happened to me.

The issues seems to cause by Windows rather than Ubuntu itself. There is a good explanation in this link:
https://wiki.archlinux.org/index.php/Samba/Troubleshooting

But I will copy & paste some of the content here, in case the link broken in the future.

======== Copy & Paste from archlinux.org, please contact me if remove is required ========

Windows 7 connectivity problems - mount error(12): cannot allocate memory

A known Windows 7 bug that causes "mount error(12): cannot allocate memory" on an otherwise perfect cifs share on the Linux end can be fixed by setting a few registry keys on the Windows box as follows:

• HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache (set to 1)
• HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\Size (set to 3)

Alternatively, start Command Prompt in Admin Mode and execute the following:

reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v "LargeSystemCache" /t REG_DWORD /d 1 /f
reg add "HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters" /v "Size" /t REG_DWORD /d 3 /f

Do one of the following for the settings to take effect:

• Restart Windows
• Restart the Server service via services.msc
• From the Command Prompt run: 'net stop lanmanserver' and 'net start lanmanserver' - The server may automatically restart after stopping it.

Note: Googling will reveal another tweak recommending users to add a key modifying the "IRPStackSize" size. This is incorrect for fixing this issue under Windows 7. Do not attempt it.

How to extend screen to second monitor in Linux / Fedora?

Here's the command that could extend the screen to second monitor, in case Linux does not do the job automatically:

xrandr --output VGA1 --mode 1920x1080 --output eDP1 --mode 1366x768 --left-of VGA1

Where you need to replace the screen size manually. By running xrandr in terminal, you could get the screen size range for each display output.

Beside --left-of, there are other options such as --above, --below, --right-of

[Alt] key problem when remote desktop Windows via Remmina

If you are using Xfce 4 and encounter the following problems using [Alt] key inside Microsoft Windows remote desktop session:

• [Alt] key does not work as per expected
• clicking [Alt] + mouse middle button move you away from your remote desktop session

then you should try this simple and straight forward trick before going too technical.

• Go Settings > Settings Manager > Window Manager Tweaks > Accessibility > "Key used to grab and move windows" > set it to "None"

Voila! Now it should works like charm. Otherwise... you might have to Google around and read about re-map key, etc.. Good luck!

Remmina - Unable to connect RDP Server

Have you ever encountered sudden failure to RDP to your Windows desktop using Remmina? There are two known reasons to me:

1. your RDP plugin for Reminna is missing. In Fedora, type sudo yum install remmina-plugins-rdp, or Ubuntu sudo apt-get install remmina-plugin-rdp. You may require to reboot after install in order to load the RDP plugin. Sometimes Import simply won't work.
2. your remote desktop's fingerprint has changed. It is impossible to reset the fingerprint within Remmina's interface. What you can do is fire up terminal, go to ~/.freerdp/ and delete known_hosts.

Now try again and voila! Your remote desktop is back!

[Fedora] Omit GUI and boot with or into command line

Before you start, you need to know what is runlevel.

runlevel is a number that indicates which mode the computer to boot into. For instance, runlevel 5 is graphical mode, where runlevel 3 is text-only mode. Runlevel 1 is single-user mode, commonly used for troubleshooting.

And GRUB (GRand Unified Bootloader), a bootloader which allow you to choose which OS to boot into during computer start up. Here's a screenshot of GRUB.

Now, there are two options:

1. boot with command line, means omit the filling up Fedora logo and show the boot progress by command line
2. boot into command line, means completely omit booting into GUI and end up in command line

What you need to do is at the GRUB screen, select your Fedora OS name and press "e".
Then find rhgb in the line start with linuxefi /vmlinuz. On the right side of rhgb should be word "quiet".

For option 1: Remove the rhgb from the line and press CTRL+X or F10. This should show the command lines as boot progress instead of the Fedora logo. Useful for identifying what has failed during boot progress. The system will still end up in GUI afterwards.

Sample = ... rhgb quiet ... 

For option 2: Here's why you have to understand the runlevel. You achieve this by simply add a runlevel number "3" after the word "quiet" (space in between two words) and press CTRL+X or F10. This should boot the system into CLI instead of GUI.

 Sample = ... rhgb quiet 3 ...

Note:

• rhgb = RedHat Graphical Boot

Enable Samba browsing in Thunar

If you enter location path start with smb:// and get a red stop sign, it means you don't have gvfs-smb install. Simply fire up your terminal and type:

sudo yum install gvfs-smb -y

You might want to install Gigolo too to manage your network folder.

sudo yum install gigolo -y

 Voila! Your address bar should work with smb:// now.

Problem connecting Xrdp

If the error appeared as "problem connecting" when connecting to remote desktop using xrdp, it is most likely the remote Linux does not have VNC server installed.

(1) To verify this, you can type:
sudo tail /var/log/xrdp-sesman.log

(2) If you see the error message below, then it means you don't have VNC server installed.
[ERROR] another Xserver is already active on display xx 

(3) To fix this, simply run this command:
sudo apt-get install tightvncserver

(4) After that, restart xrdp service by running:
sudo service xrdp restart

Here's why:
xrdp is the daemon that handles RDP remote desktop access from Windows machines to your Linux Mint PC. But it's not enough to install only xrdp - you need a VNC server. Unfortunately it's not automatically installed with the xrdp package.

The error message "error - problem connecting" after a successful login message isn't very helpful either. Searching the Internet can drive you in circles - I wasted at least 2 hours on finding out that I forgot to install the VNC server - ouch.

Thanks powerhouse from Linux Mint forum who shared this useful information.