[Ocfs2-users] OCFS2 benchmark slow concurrent write
Philipp Wehrheim
wehrheim at glue.ch
Wed Jun 13 23:21:47 PDT 2007
Hi everbody,
I've just created a test setup for my company with two pc's drbd (0.8.3)
primary/primary mode with OCFS2 on top of it. the pc's are running suse
10.2 with kernel 2.6.21.2. the Hardware CPU ~1GHz ~12 MBRam and one NIC
(100Mbit).
The setup is working quite stable and so I started to make some
benchmarks and received some strange results:
For the benchmark I used a small C-prog "iotest" that, in a loop, open a
file write on line and closes the file again.
---
#define LOOPCOUNT 1050620
...
for (i=0; i<LOOPCOUNT; i++) {
if ( (logFD = open (LOGFILE, O_WRONLY|O_CREAT|O_APPEND, 0666)) !=
-1) {
write (logFD, logMSG, logLEN);
close (logFD);
}
---
1. write to a ext3-fs
| per line | for 1050620 lines |
hobbes | 44 nanoseconds | 47.1 seconds |
struppi | 37 nanoseconds | 39.3 seconds |
2. write to a OCFS2-fs single -> only one maschiene at the time
| per line | for 1050620 lines |
hobbes | 84 nanoseconds | 88.3 seconds |
struppi | 47 nanoseconds | 50.1 seconds |
3. write to a OCFS2-fs into _ONE_ file -> concurrent write from both pcs
| per line | for 1050620 lines |
hobbes | 113 milliseconds | 119764 seconds | yes over 33h
struppi | 113 milliseconds | 119764 seconds |
4. write to a OCFS2-fs into two files -> each pc into one file
| per line | for 1050620 lines |
hobbes | 93,6 nanoseconds | 98.6 seconds |
struppi | 59,5 nanoseconds | 62.6 seconds |
So as one can see OCFS2 does quite good but when it comes to concurrent
writes into one file it is sloooooowwwwwwww.
The question is now:
- is there an error in my setup
- how can i tune ocfs2
- how can i tune dlm
- WHERE IS THE OCFS2 DOCU???(no im not talking about colorful powerpoint slides)
Thanks in advance
Philipp
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