Re: [BackupPC-users] backuppc slow rsync speeds

[Timothy J M. <tm...@ob...>]

<bac...@ko...> wrote on 09/18/2012 09:51:11 PM:

> Timothy J Massey wrote at about 12:54:35 -0400 on Monday, September 17, 
2012:
>  > I have several very similar configurations.  Here's an example:
>  > 
>  > Atom D510 (1.66GHz x 2 Cores)
>  > 4GB RAM
>  > CentOS 6 64-bit
>  > 4 x 2TB Seagate SATA drives in RAID-6 configuration
>  >         I get almost 200 MB/s transfer rate from this array...
>  > 2 x Intel e1000 NICs in bonded mode.
>  > 
> 
> I snipped out most of Tim's original post because it seems that nobody
> has referenced the fact that he is using pretty low powered
> chips. Certainly, I could understand how compression would be slow on
> these chips and could be the rate limiting steps.

You are correct.  I've said from the beginning that this is *embedded* 
class hardware.  I'm trying to figure out exactly what I can-or have 
to--do to make this work.

Again, I know that I can throw hardware at this;  I don't want to.  I want 
to find what I can do to tweak my settings for an acceptable level of 
performance.  If I can't, then I will address the hardware, and be 
confident that I understand why I am.

> Tom's Hardware benchmarked the Atom D510 against circa year 2000
> Pentium 4 single core processors and found that for non-multithreaded
> programs that don't take advantage of new instruction set
> enhancements, they are pretty equivalent.

Ouch.  I guess I bought into the Intel hype too much...  :(

I wasn't expecting insane performance.  But I admit I was expecting 
Core-type performance rather than Pentium 4!  It sounds like I'm actually 
getting Pentium III performance, though.  (Which makes sense:  the Pentium 
M was a development of the Pentium III, and it wouldn't surprise me if the 
Atom--designed for ultramobile--had more in common with the Pentium M than 
Core...)

> So, I wouldn't be surprised if the problem is using a "netbook"
> category performance processor to perform a computationally intensive
> server-type job...

Nor would I.  At all.  But throwing hardware at it is not really answering 
the question, it's more addressing the symptom.

Besides, from someone who has run BackupPC on a wall wart, I would have 
expected more interest in the challenge!  :)

>From my limited testing, I was able to get 4 x performance simply by 
disabling compression.  That takes my 4-day fulls and makes them 1-day. If 
I can possibly double the performance again, I get down to 12 hours. 
Mission accomplished.  So, I'll keep tweaking.

As a bit of a sanity check for me, the motherboard I'm using (SuperMicro 
X7SPA-HO-F) has an Atom D510 and is $175.  A SuperMicro X9SPV-LN4F-3LE 
with 3rd Gen Core i7-3612QE is $800.  The lowest-end X9SPV with an i3 is 
$600.  Given that the target price for the entire device is $1200 or so, 
that's a tough fit...  Which is why I'm trying to make the inexpensive, 
compact, cool and quiet Atom-based boards work.

Timothy J. Massey


 
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