Blog Posts

How To Install and Boot Microsoft Windows Server 2019 from Persistent Memory

• How to

In a previous post  I described how to install and boot Fedora Linux using only Persistent Memory, no SSDs are required. For this follow on post, I attempted to install Microsoft Windows Server 2019 and 2022 onto the persistent memory.

TL;DR - I was able to select the PMem devices as the install disk, but when the installer begins to write data, we get an “Error code: 0xC0000005”. I haven’t found a solution to this problem (yet).

How to Boot Linux from Intel® Optane™ Persistent Memory

• How to , Linux

Introduction

In this article, I will demonstrate how to configure a system with Intel Optane Persistent Memory (PMem) and use part of the PMem as a boot device. This little known feature can reduce boot times for those that need it.

The basic steps include:

• Configure the Persistent Memory in AppDirect Interleaved
• Create two small SECTOR namespaces, one per Region
• Install the OS and select one or both of the namespaces (single disk install, or mirrored LVM)

Configure the Persistent Memory

The following figure shows how we will provision the persistent memory.

How to Boot Linux from Intel® Optane™ Persistent Memory

• How to , Linux

Introduction

In this article, I will demonstrate how to configure a system with Intel Optane Persistent Memory (PMem) and use part of the PMem as a boot device. This little known feature can reduce boot times for those that need it.

The basic steps include:

• Configure the Persistent Memory in AppDirect Interleaved

• Create two small SECTOR namespaces, one per Region

• Install the OS and select one or both of the namespaces (single disk install, or mirrored LVM)

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How To Install and Boot VMWare VSphere/ESXi from Persistent Memory (or not)

• How to

In a previous post I described how to install and boot Linux using only Persistent Memory, no SSDs are required. For this follow on post, I attempted to install VMWare VSphere/ESXi v7.0u2 onto the persistent memory.

TL;DR - It doesn’t work. The installer doesn’t list the PMem devices, and I was unable to find a way to manually select the PMem device(s).

I assume you followed the previous post to configure sector namespaces that we’ll use to install ESXi.

How To Install and Boot VMWare VSphere/ESXi from Persistent Memory (or not)

• How to

In a previous post I described how to install and boot Linux using only Persistent Memory, no SSDs are required. For this follow on post, I attempted to install VMWare VSphere/ESXi v7.0u2 onto the persistent memory.

TL;DR - It doesn’t work. The installer doesn’t list the PMem devices, and I was unable to find a way to manually select the PMem device(s).

I assume you followed the previous post to configure sector namespaces that we’ll use to install ESXi.

How to build an upstream Fedora Kernel from source

• Steve Scargall
• How to , Linux

I typically keep my Fedora system current, updating it once every week or two. More recently, I wanted to test the Idle Page Tracking feature, but this wasn’t enabled in the default kernel provided by Fedora.

# grep CONFIG_IDLE_PAGE_TRACKING /boot/config-$(uname -r)
# CONFIG_IDLE_PAGE_TRACKING is not set

To enable the feature, we need to build a custom kernel with the feature(s) we need. Thankfully, the process isn’t too difficult.

For this walk through, I’ll be building a customised version of the Fedora 32 kernel version I already have installed (5.8.7-200.fc32.x86_64), using some of the instructions from https://fedoraproject.org/wiki/Building_a_custom_kernel .

Linux Device Mapper WriteCache (dm-writecache) performance improvements in Linux Kernel 5.8

• Steve Scargall
• How to , Linux

The Linux ‘dm-writecache’ target allows for writeback caching of newly written data to an SSD or NVMe using persistent memory will achieve much better performance in Linux Kernel 5.8.

Red Hat developer Mikulas Patocka has been working to enhance the dm-writecache performance using Intel Optane Persistent Memory (PMem) as the cache device.

The performance optimization now queued for Linux 5.8 is making use of CLFLUSHOPT within dm-writecache when available instead of MOVNTI. CLFLUSHOPT is one of Intel’s persistent memory instructions that allows for optimized flushing of cache lines by supporting greater concurrency. The CLFLUSHOPT instruction has been supported on Intel servers since Skylake and on AMD since Zen.

"ipmctl show -memoryresources" returns "Error: GetMemoryResourcesInfo Failed"

• Steve Scargall
• Linux , Troubleshooting

Issue:

Running ipmctl show -memoryresources returns an error similar to the following:

# ipmctl show -memoryresources

Error: GetMemoryResourcesInfo Failed

Applies To:

• Linux & Microsoft Windows

• Intel Optane Persistent Memory

• ipmctl utility

Cause:

The Platform Configuration Data (PCD) is invalid or has been erased using a previously executed ipmctl delete -dimm -pcd command or the system has new persistent memory modules that have not been initialized yet.

A module with an empty PCD will show information similar to the following. This shows an example of PCD of DIMM ID 0x0001. To review the PCD for all modules in the system use ipmctl show -dimm -pcd.