Adding a virtual bridge

We have seen the networking components used in Proxmox; we went through the configuration file and saw how those components come together. We are now going to create a new virtual bridge for our cluster. We will use this bridge to create an isolated network later on in this book. Perform the following steps to create a virtual bridge in Proxmox:

  1. Securely log in to the node pmxvm01.
  2. Open the interface file # nano /etc/network/interfaces using an editor.
  3. Add the following lines at the end of the file:
    auto vmbr200
    iface vmbr1 inet static
            bridge_ports none
            bridge_stp off
            bridge_fd 0
  4. Save the file and exit the editor
  5. Activate the bridge from the CLI using the following command:
    # ifup vmbr200
  6. Do the same for the second node pmxvm02 …

How to Install Zenoss 4.2.5 on Ubuntu 14.04

I recently had the need to resurrect Zenoss. I have a post for how to get an older version of Zenoss working on Ubuntu 12.04, but the links to Hydruid’s blog that had the real info are all dead now. Luckily the installer scripts are current and available on his Github.

First, I pulled down a copy of Hydruid’s install script to review and modify if needed.


It follows the same process as the previous version that I used.

  1. Update Ubuntu
  2. Setup zenoss user
  3. Install package dependencies
  4. Install Zenoss Core 4.2.5-2108_03c
  5. Setup MySQL database, import data, setup user and permissions
  6. Install and configure RabbitMQ
  7. Post-install tweaks

Looks good to me. Make the script executable and fire it off. Here we go!

sudo chmod +x
sudo ./ 2>&1 | tee script-log.txt

My terminal barfed up a bunch of text. I had to approve the Java installer and setup a root password for MySQL as part of the install process.

...Check log didn't find any errors

The Zenoss 4.2.5 core-autodeploy script for Ubuntu is complete!!!
A backup script ( has been placed in the zenoss user home directory.

Browse to to access your new Zenoss install.
The default login is:
  username: admin
  password: zenoss

No critical errors. Sweet!

I browsed to the site and it came right up. Time to get configuring…
Step 1: Change the password!


Windows 10, ‘System’ process taking massive amounts of RAM

I’ve looked at xperf traces of several users and here the function ntoskrnl.exe!SmKmStoreHelperWorker of the Kernel starts to allocate memory.

(Click image to enlarge)

I discovered this on sysinternals.

I’ve asked Microsoft about it and the answer is that this is by design. It is related to System Memory compression.

In the announcement of Windows 10 Build 10525, Microsoft explained it a bit:

In Windows 10, we have added a new concept in the Memory Manager called a compression store, which is an in-memory collection of compressed pages. This means that when Memory Manager feels memory pressure, it will compress unused pages instead of writing them to disk. This reduces the amount of memory used per process, allowing Windows 10 to maintain more applications in physical memory at a time. This also helps provide better responsiveness across Windows 10. The compression store lives in the System process’s working set. Since the system process holds the store in memory, its working set grows larger exactly when memory is being made available for other processes. This is visible in Task Manager and the reason the System process appears to be consuming more memory than previous releases.

So instead of writing memory data to the pagefile it compresses them. And this compressed memory is shown in the System process.

Microsoft also posted more details in the inside hub. Winbeta created a article which includes more details.

Apparently, the reason for this happened to do with Microsoft choosing to suspended UWP apps when they were not in the foreground, very similar to some smartphone OS management. Windows 8 users understood (perhaps not) that if apps weren’t on screen, they wouldn’t run until the user switched back to them. The ‘all or nothing’ approach is being updated with Windows 10 introducing a layer between the pagefile and normal paging activity. Now, when faced with memory pressure issues, MM will determine which pages should be moved to the modified list in a process called trimming. The modified list is a secondary list of pagefiles backing up a list of standby pagefiles. A backup list is captured in case memory is reclaimed from the standby list by another process, and the original process comes looking for its page. Instead of all or nothing, Windows 10 MM will compress unused pages rather than writing them to disk. With less writing, the result should be fewer disk operations – thanks to the compression – and now more data can be stored in memory.

enter image description here

According to the Windows team, “In practice, compressed memory takes up about40% of the uncompressed size, and as a result of a typical device running a typical workload, Windows 10 writes pages out to disk only 50% as often as previous versions of the OS.” If all goes according to plan, Windows users could be experiencing reduced waiting times for all devices as well as extended lifespans on systems that have flash-based hard drives.

Decompression is also something Windows 10 is designed to do well. Windows 10 is using the combination of parallelizability and sequential reads to produce pages into memory once called. The new decompression should result in a speedier experience as Windows 10 is simultaneously decompressing data and reading it in parallel using multiple CPUs. Older versions of Windows may have felt sluggish because of the transfer rates between the disk.

Microsoft also released a Video on channel9 which explains the feature.

Memory Compression in Windows 10 RTM

In this video Mehmet Iyigun spent some time discussing why the System process in Windows 10 is taking a bit more memory and why it’s a good thing. A process taking more memory sounds like a bad thing – that is until I understood more about memory management, paging, and hard / soft page faults. Turns out that that the OS is doing some clever optimizations that allow your processes to trim some of the memory but not necessarily page it out to disk. Not only is the memory preserved in RAM, but it is also compressed – making hard page faults a more rare occurrence. The results should make for a snappier experience.

In the latest TH2 Builds, Microsoft updated the description in the task manager and now also shows that the SYSTEM process hosts the compressed memory:

enter image description here

to avoid confusions about the “high” usage.