Optane
How To Enable Debug Logging in ipmctl
The ipmctl utility is used for configuring and managing Intel Optane Persistent Memory modules (DCPMM/PMem). It supports the functionality to:
- Discover Persistent Memory on the server
- Provision the persistent memory configuration
- View and update the firmware on the persistent memory modules
- Configure data-at-rest security
- Track health and performance of the persistent memory modules
- Debug and troubleshoot persistent memory modules
I wrote the IPMCTL User Guide showing how to use the tool, but what if ipmctl returns an error or something you’re not expecting? How do you debug the debugger? On Linux, ipmctl relies on libndctl to help perform communication to the BIOS and persistent memory modules themselves. This is a complicated stack involving multiple kernel drivers and the physical hardware itself. Anything along this path could be causing a problem.
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How To Install and Boot Microsoft Windows Server 2019 from Persistent Memory
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).
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How To Install and Boot Microsoft Windows Server 2022 from Persistent Memory (or not)
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 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).
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How To Install and Boot Microsoft Windows Server 2022 from Persistent Memory (or not)
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 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).
Read More
How To Install and Boot Microsoft Windows Server 2019 from Persistent Memory
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).
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How to Boot Linux from Intel® Optane™ Persistent Memory
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.
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How to Boot Linux from Intel® Optane™ Persistent Memory
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)
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.
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How To Install and Boot VMWare VSphere/ESXi from Persistent Memory (or not)
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.
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Linux Device Mapper WriteCache (dm-writecache) performance improvements in Linux Kernel 5.8
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.
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"ipmctl show -memoryresources" returns "Error: GetMemoryResourcesInfo Failed"
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.
Intel Optane Persistent Memory Modules report "Non-functional" state in ipmctl
Issue
Executing ipmctl show-dimm to get device information shows the persistent memory modules in a ‘Non-functional’ health state, eg:
# ipmctl show -dimm
DimmID | Capacity | HealthState | ActionRequired | LockState | FWVersion
=============================================================================
0x0001 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x0011 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x0021 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x0101 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x0111 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x0121 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x1001 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x1011 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x1021 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x1101 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x1111 | 0.0 GiB | Non-functional | N/A | N/A | N/A
0x1121 | 0.0 GiB | Non-functional | N/A | N/A | N/A
Other ipmctl commands may fail and return “No functional DIMMs in the system.”, eg: