[DRBD-user] Re: Why is drbd 0.7.22 slow on Opteron 240 EE?

Maurice Volaski mvolaski at aecom.yu.edu
Wed Nov 22 08:55:54 CET 2006

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

>I suggest you
># wget http://svn.drbd.org/drbd/trunk/benchmark/dm.c
># gcc -O -o dm dm.c
>and then to benchmark:
>  ./dm -x -a 0 -s 4g -b 20m -m -y -p -o /maurice/bonnie/hello

Here are the results for the two computers

primary (faster one)
29.34 MB/sec (4294967296 B / 02:19.620474)

secondary (slower one)
34.57 MB/sec (4294967296 B / 01:58.497313)

How can such a fast I/O subsystem as a RAID 6 set of Seagate 750 GB 
SATAII (3Gbs) drives off an Areca PCIe controller get such dismal 

And why do they contradict the much faster results from dd?

For another point of contraction, though less so because it tests 
just reads, here are hdparm -t test results

primary (faster one)
Timing buffered disk reads:  426 MB in  3.01 seconds = 141.44 MB/sec

secondary (slower one)
Timing buffered disk reads:  362 MB in  3.01 seconds = 120.45 MB/sec

Maurice Volaski, mvolaski at aecom.yu.edu
Computing Support, Rose F. Kennedy Center
Albert Einstein College of Medicine of Yeshiva University

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