Hello in this video I want to follow up on a previous video I made where I installed some
SSD cache in a Synology DS918+
NAS and I did some
sort of kind of benchmarks to try and see if there was any speed gain, and I didn't get
Results that showed that I was getting
Any significant speed gain with the system, so people left me some comments on there
which were pretty helpful, and I think the reason was is that I'm
accessing the NAS over a Gigabit Ethernet and
the
Theoretical top speed of Gigabit Ethernet is 125
megabytes per second and
I was getting 80 megabytes per second
And I think that's just the top speed of my network because you won't really get to the theoretical
Top speed of it, so I think that was the speed
My top speed. I think was maxing out my network, so I've come up with some other tests
to kind of show the cache working so
I'll look at that now. I'm going to be
accessing the nest using SSH so if you're not familiar with that how to get to that if
You go to the control panel and click Advanced Mode
You'll see this
terminal and
SNMP
If you open that up, you can enable SSH service on your NAS device, and this I'm not going to go through how to use
SSH but
You know if you have questions you can leave them in the comments, but you can Google how to do that
but I'm in a terminal and I've
gotten into the
Synology NAS here, and I've created a folder, and I'm going to
create a file
And this will kind of test the write speed so I'll say
DD in file equals /dev/zero so I'm going to
Be pulling from this device that just creates zeroes on a server. This is on pretty much any UNIX system
And they'll say out file equals
temp.txt I'll
say
BS or bite size equals 1 Meg and I'll say count equals 100 so this will create
Approximately like a 100 megabyte file, so I'll run this and we'll see that that
Copied to the drive in
1.1 Gigabytes per second so that would indicate to me that
The cache is working the write cache
Because the spinny hard drives. I don't think would run that fast so now we can read that back
We can say DD in
File equals
temp out file equals
/dev/null and that that's a kind of a bottomless pit that you can
Say copy things in too, but it's extremely fast because you're not actually copying to any drive
So we'll run this and we'll see it says
639
megabytes per second and
Right again. This is 650 megabytes per second, so that is also
Would make me think it's using SSD so
Now I'm going to find a file on the server. I have not accessed so
I'm gonna find that I'll jump cut the video
after I find that and we'll do some testing with it ok so I
Look through my hard drive, and I found an ISO
For FreeNAS which I thought would be funny to do so I have here
I've selected a it's I think it's around a six hundred megabyte file
and I'm reading that in and I'm outputting it to dev null so I will run this and
This should be pulling from the regular hard drives
So we see here that we had a read speed of
219 megabytes per second so if this loaded into the cache and we run it again
We should see a higher speed which we did
566 megabytes per second, and I don't think running it again would
It's speeded up slightly. I don't know
That's probably not a huge deal, so
This seems to tell me that the cache is working so this was probably the speed
You know from the hard drives and this would be the speeds from the SSD
Here so what this is showing me is that?
These SSDs likely won't
Speed up my network access
Although for like random reads it could maybe that could help
It's hard to say how that would all work out, but I think a big advantage of these would be
For using virtualization on it, which I am using some virtualization
I plan to use more
Because that's accessing everything locally within the machine so when using virtualization you are limited by
The hard drive speed having these caches on there should speed everything up, so
This is just a you know quick simple test. I kind of came up with
Because I want to do you have some numbers that show that the cache was actually doing something
But certainly if you have any you know comments or questions leave them below. I really like reading
What people's thoughts are on all this
Or if you have any specific benchmarks you want me to run I could probably try those. I don't plan on
Removing the cache to try these tests without the cache in that's kind of a hassle
But I don't think I would have gotten numbers like this
You know if it wasn't doing some sort of caching so but you know if you disagree with me
leave the comment below and we'll talk about it so I
Appreciate everyone watching and I'll put a link below to my playlist so you can watch my other videos and thanks for watching bye