[GTALUG] New Desktop PC -- debian Linux - Proposed 2 TB HDD Partitioning;

[Russell]

On April 17, 2018 9:02:14 AM CDT, lsorense at csclub.uwaterloo.ca wrote:
>On Tue, Apr 17, 2018 at 08:20:47AM -0400, Russell via talk wrote:
>> Currently I have two versions of the same os on the same machine. One
>on M.2 Xpoint nvram and one on a standard SSD. I'm playing around with
>tweaking before I do a final config. So far the Xpoint direct hw access
>appears 3x as fast as the SSD while real world throughput shows up
>about twice as fast on the Xpoint, recent INTEL cache fencing
>notwithstanding.
>> 
>> dd if=/dev/zero bs=1M count=1024 | md5sum
>> 1024+0 records in
>> 1024+0 records out
>> 1073741824 bytes (1.1 GB, 1.0 GiB) copied, 1.35008 s, 795 MB/s
>> cd573cfaace07e7949bc0c46028904ff  -
>> 
>> 795 is just under twice as fast as writing to the conventional SSD.
>
>That command didn't write anything to anywhere.

It wrote a bunch of zeros to a virtual file. Perhaps even touching a tmp file along the way. Even if it didnt touch tmp, it wrote the zeros someplace in order to perform the count.

I was just trying to comment on the speeds of the two installs relative to the respective  disks the OS runs from. I'm sorry you didn't understand that. Perhaps I should have said running the OS from the two different drives, irrespective of all the other disk writes which may happen when the OS operates normally when calling dd from a GUI.
>
>It tests how fast md5sum can calculate the checksum of 1GB of zeroes.
>
>Certainly in no way testing any disk speed.  Reasonable test of CPU and
>ram speed perhaps.

Often tests provide side channel results which are not part of the expected normal metric but quantifiable data arises none the less.

My appologies for the misunderstanding. 
>
>-- 
>Len Sorensen

-- 
Russell