Download Speed with Kubuntu Karmic 64bit

[Steven Vollom]

Trim again
> (I haven't read the whole thread and am hoping that this isn't too
> redundant.)

So far, it seems the most informative.

> > OK, here are the basics:
> During a copy, the available RAM will be used as a buffer. While
> there is free RAM, the copy operation will seem to progress at the
> speed the source drive can be read from.

A while back, there was a thunder storm.  When I returned home I had to reset 
the main breaker.  Of course the computers were off.  After that it was quite a 
while before I got the system restored.  The result was My outer two slots for 
memory seem to have been toasted.  In any event, I was reduced to 4gb of ram 
instead of 8gb.  That being said, I also was getting help from a friend in 
South Africa who was having terrific success with ext4 in his AMD 64bit system.  
He said he had used it for months without any problems and enjoyed much 
greater transfer speeds.  I had to fresh install anyway, so I chose ext4.

I haven't been problem free in the time that passed, however, no one mentioned 
the ext4 as a problem for the problems I have been helped with, and my 
transfer speeds have more than doubled since the change, so I haven't 
considered changing back.

From previous computers, the amount of ram at 4gb is so great that I hadn't 
considered a shortage or cache shortage.  I have an AMD quad 9600 with, I 
believe 512mb of cashe for each of four processors and a 20gb swap file for my 
own reasons.  So, the thought of running out of cache or ram hadn't hit me 
yet.

Both my HDD's are SATA with 600gb vacant on one and 400gb unused on the other, 
so I don't think there is any shortage of space, and perhaps the reason I get 
such wonderful speeds most of the time.  Each has cache, but I can not 
remember the amount right now.

One thought I had was that I have heard that the HDD's are not constantly 
running at 7200rpms.  I thought perhaps when they slowed and before the power 
was speeding them again, that that was cause for dips in speed.  Your idea of 
cache shortage makes more sense to me though.

I don't know for a fact, but I don't think the drives operate on the same bus, 
but I do not know.

I usually have several applications running at the same time, so next time I 
run a large file to backup, I will shut down everything else to see if it shows 
an increase.

I believe the file system has been running stable, so I will retain it until I 
find that it is causing problems.  Before I installed ext4, transfer rates were 
anywhere from 20 to 60mbps with very occasional and brief spikes to 79mbps at 
the fastest.  Now transfers take place usually around 120 to 130mbps with 
occasional relatively sustained speeds around 150mbps.  On a couple of 
occasions transfer went to 180mbps and sustained the speed for all but part of 
1 second on a 1.4gb transfer which finished in just over 10 seconds.  It will 
spike to 170 to 180mbps, but rarely sustains at that speed for more than a few 
seconds at most.

I realize equipment has advance greatly since I built my computer, but I am 
trying to learn how to maximize transfers without over-clocking anything.  My 
motherboard is an ASUS M3N-HT Mempipe and has many different ways to over-clock 
many different chips.  I haven't even looked at those features yet.  If I use 
them, it will be only to optimize the system; I am not a gamer.  Perhaps it 
will be efficient to slow a chip a bit to make it more compatible with the 
others.  If so, that is what I will do.

Thanks for the info, I am going to work with this until it no longer seems 
interesting.

Trim

> Since KDE starts a new copy
> operation for every file and does a lot of "useless" work in between
> operations (for progress information), copying a large amount of
> small files will take much longer using the KDE copy than using the
> cp command.

I am just learning to use the konsole more.  I will use the cp command from 
now on, if it is faster and/or better.

> This is partially due to the buffering mentioned above. Also,
> obviously, the target drive's write speed is a limiting factor.
>
Both drives are Maxtor SATA's a 1.5tb and a 500gb.  The 500gb is the backup 
drive and most large file transfers take place from the larger to smaller 
drive.  Both have the same specifications, as i recall.  I am going to check 
that.
Trim

> > I have read that ext4 is not stable;
> 
> That is incorrect. It isn't tested as thoroughly as its predecessors,
> but it most certainly is stable (there was some patch in the Ubuntu
> 9.04 kernel which rendered deleting unstable, but that was an
> exception).

I have been successfully using ext4 for over 6 months now with no negative 
impact that I am aware of.  Perhaps my experience is useful for the 
developers.  I transfer lots of large files.
> 
Trim
> 
> There is a lot of theory behind the inner workings of a computer, and
> you don't always need to use something to be able to apprehend
> problems.
> Also, not using something because it's not well-tested is a *very*
> valid reason and the one I've come across most often.

I am retired.  Most of my joy is derived from learning to use and using a 
computer.  I don't even mind crashing and re-installing, as long as I am not 
unable to use my computer for too long a period of time.
> 
>   --Reinhold
>