Welcome.
My name is Eduardo Berrocal from Intel.
In this video I give you an introduction to the new Intel
Optane DC Persistent memory.
A new class of memory for the next generation of Intel Xeon
server processors.
Intel Optane DC Persistent Memory
is a new type of persistent memory sometimes called
a storage class memory.
This new memory has two main properties.
First, it is persistent.
This means that data is maintained even
when the system power is off.
In addition, this memory is byte-addressable.
Like in regular DRAM, programs can
access data structures in place at cache line granularity,
avoiding the need to access data in large blocks
as it clearly happens in traditional I/O.
Optane technology reduces access latency
substantially, so much so that software
which usually contributes at very more proportion
relative to the overall access latency for NAND
such as this start to be the major bottleneck
in the case of Optane SSDs.
Persistent memory connects directly
to the memory box of the CPU, in effect, getting rid
of any software bottleneck.
You can see how low the latency is for a cache
line read of 64 bytes.
For a fair comparison, the latency
for a block read of 4 kilobytes is also shown.
Persistent memory can be used in three modes, memory mode,
application direct, or app-direct mode,
and mixed mode, which is a combination of the two.
Memory mode allows the system to use persistent memory
as main memory.
In this case, DRAM is used as a cache and cannot be explicitly
managed by the operating system.
This mode is appealing for use cases
where applications need more memory,
but expanding the system's memory with only DRAM
becomes either very expensive or right away impossible
due to scaling problems.
The advantage of memory mode for applications
is that no code modifications are necessary, however,
data is not persistent in this mode.
In app-direct mode, persistent memory
is exposed as a special block devices to the OS.
And applications can use such devises for data persistent.
In this case, DRAM is still used as main memory.
The advantages for applications are twofold.
First, you get persistence for your data structures
without the need of traditional I/O. Second,
and in the case where persistent is not a requirement,
applications can control the way data is
stored in these different memory tiers.
For example, we can put so-called hot objects
those that are used the most in DRAM,
while leaving warm objects for persistent memory.
You can also use persistent memory in app-direct
as a regular block device and put a regular file system on it
as if it were an SSD.
It is even possible to boot an operating system
from it, which allows you to configure systems
with no disks are all.
In terms of security, data in Intel Optane DC Persistent
memory is protected at all times with xts aes 256 encryption,
with the key safely store in the controller of each module.
For app-direct, a passphrase is required after every power
cycle to unlock the key.
In the case of memory mode, keys are cleared and regenerated
in every power cycle to make the data appear volatile.
Before you can start using persistent memory
you need to have several hardware and software
components in place.
First, you need a server with either a gold or a platinum
model of the next generation Intel Xeon Server CPU.
Be aware that there are some restrictions
in the way persistent memory can be used,
depending on the CPU model.
Second, you need an operating system
with the proper drivers installed on it.
Fortunately, the most common operating systems
used in the data center today such as Windows Server
and Linux [INAUDIBLE] such as Red Hat, CentOS, Ubuntu,
and Suse, as well as Hypervisors, such as VMware,
ESXi, or Hyper-V are ready support persistent memory out
of the box.
Finally, and only if you plan to use app-direct,
you will need a persistent memory aware file system.
You will be glad to know that the most common file
systems such as ext2, ext4, and xfs in Linux and NTFS
in Windows are already enabled for persistent memory.
At this point, you might be wondering
why do we need a file system?
After all, the whole point of putting persistent memory
on the memory bus was to get rid of the software stack
in the first place, which of course, includes a file system.
The reason for the need of a persistent memory aware file
system is tightly coupled with the programming
model used for system memory.
To expand on the information covered in this video,
please read the documentation provided in the links.
[INTEL JINGLE]