[tahoe-dev] Performance question: reading from/writing to a grid of 4 data centers using 9-out-of-24 coding

[Ed Kapitein]

Hi Robin,

I am quiet new too, and i ran into a "out of memory" situation, while
reading a large file.
Did you check to see if the reading machine starts swapping?
( you can check with top )
That could make the machine and the reading real slow.

Kind regards,
Ed

On Mon, 2013-03-04 at 10:45 -0500, Robin Chen wrote:
> Hi,
> 
> 
> I have recently started my experiments with Tahoe and deployed 24
> Tahoe storage nodes in 4 data centers (using 9 out-of 24 coding), but
> I'm running into a performance problem.
> 
> 
> I'm new to this email list, so I'm not sure if this problem has been
> discussed before or not.
> 
> 
> I would expect the "reading" performance (reading 9 shares) to be
> better than the "writing" performance (writing 24 shares in 4
> geographically-distribute data centers), but the reading time is
> typically two times longer in most of my tests with files > 300MB.
> 
> 
> For example, for a file size of 383MB,  I'm getting about 16Mbps in
> throughput for writing, but only about 8.8Mbps in reading.    
> 
> 
> Any possible explanation?    
> 
> 
> Thanks!
> 
> 
> Robin
> _______________________________________________
> tahoe-dev mailing list
> tahoe-dev at tahoe-lafs.org
> https://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev