Mailinglist Archive: opensuse (908 mails)

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Re: [opensuse] Gobs of RAM?
On Fri, Jun 3, 2016 at 2:14 PM, Lew Wolfgang <wolfgang@xxxxxxxxxxxxxxx> wrote:
E7-8893v3

Per Intel:
Recommended Customer Price $6841.00

So, over $25K just for the 4 CPUs

Probably over $50K for the RAM.

This is one hell of a machine you are talking about.

All quad (or dual) socket servers are NUMA as I understand it. If you
read the link I sent a big part of the issue is if one of the sockets
runs out of work to do (ie. there aren't 8 threads scheduled to it),
then the scheduler may fail to move new threads to it for seconds.
That is even in the case of all the threads being independent. The
Linux scheduler in the mainline kernel is simply not doing a good job
of manager the NUMA thread pools.

== next question ==

Is there much disk i/o? If so, NVMe SSDs are what you "want" for storage.

The price is way down. A 128GB NVMe SSD from Samsung is under $100.
(Scale up as needed.) NVMe solutions were in the thousands minimum a
couple years ago.

read these 2 posts about NVMe design from last night on the factory list:

http://markmail.org/message/owyjv7di4ilss7bk
http://markmail.org/message/wqpnm3yhyugm34ek

== Highlevel data storage info ==

I've let myself get behind, but I think this is right.

=> SCSI
/dev/sdx Been around forever, very feature rich. /dev/sdx
originally meant SCSI disk x

=> IDE
/dev/hdx The old ide drivers. Very popular 2000-2005.

=> SATA
/dev/sdx Sata was IDE on steroids from a feature perspective. So
much so, it was layered under the SCSI driver as libata instead of
living in the old ide driver code.

=> NVMe
/dev/nvme The newest thing under the sun. Designed explicitly to
support highspeed SSDs and have direct connections to the PCIe bus.
An entire new linux driver had to be developed.

/dev/nvme0 is the 1st NVMe drive in your system,
/dev/nvme0n1 is the 1st namespace (similar to a SCSI LUN) on that drive
/dev/nvme0n1p1 is the 1st partition in that namespace.

NVMe has a theoretical max speed of 10 GB/sec (iirc)

Real world is above 1 GB/sec at affordable costs.

I saw a laptop earlier this week with a 500GB NVMe SSD. (Made by Alienware).

Greg
--
Greg Freemyer
www.IntelligentAvatar.net
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