[DRBD-user] speed problem...

PEYRICHOU R Ext OCISI rpeyrichou.ext at francetelecom.com
Wed May 19 17:36:18 CEST 2004

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


Hello

I'm trying to set up a drbd configuration... and i have some throughput problems...

so, i have :
- 2 IBM x345 servers biPIV 2.4G
- with 2GB of ram,
- RAID0 HDD's on 3 hot plug SCSI 80GB (ultra fast somethink 320)

And, i'm trying to set up a drbd mirroring over the native intel GBit ethernet interfaces.

I've tested the network with ttcp and the result is good (115MB/sec) :

[root at server1 ttcp]# ttcp -t -s 192.168.7.61
ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5001  tcp  -> 192.168.7.61
ttcp-t: socket
ttcp-t: connect
ttcp-t: 16777216 bytes in 0.14 real seconds = 115350.23 KB/sec +++
ttcp-t: 2048 I/O calls, msec/call = 0.07, calls/sec = 14418.78
ttcp-t: 0.0user 0.0sys 0:00real 42% 0i+0d 0maxrss 0+2pf 0+0csw

I've tested my hdd with tiobench:
so here are the Sequential Write results:
-local HDD:
2.4.9-e.35smp                  10   4096    1   48.49 33.94%     0.021        0.12   0.00000  0.00000   143
2.4.9-e.35smp                  10   4096    2   40.74 57.03%     0.041        0.15   0.00000  0.00000    71
2.4.9-e.35smp                  10   4096    4   36.40 136.4%     0.092        0.36   0.00000  0.00000    27
2.4.9-e.35smp                  10   4096    8   40.99 133.2%     0.088        0.29   0.00000  0.00000    31
2.4.9-e.35smp                  10   4096   16   55.90 143.2%     0.095       60.76   0.00000  0.00000    39
2.4.9-e.35smp                  10   4096   32   35.72 114.9%     0.108      113.60   0.00000  0.00000    31
2.4.9-e.35smp                  10   4096   64   27.32 105.8%     0.171      268.23   0.00000  0.00000    26
-with drbd mode A:
2.4.9-e.35smp                  10   4096    1   22.99 20.69%     0.021        0.10   0.00000  0.00000   111
2.4.9-e.35smp                  10   4096    2   20.61 39.15%     0.041        0.14   0.00000  0.00000    53
2.4.9-e.35smp                  10   4096    4   15.93 57.76%     0.092        0.34   0.00000  0.00000    28
2.4.9-e.35smp                  10   4096    8   16.47 61.75%     0.104       22.25   0.00000  0.00000    27
2.4.9-e.35smp                  10   4096   16   17.21 47.32%     0.085        0.67   0.00000  0.00000    36
2.4.9-e.35smp                  10   4096   32    6.24 20.68%     0.128       55.81   0.00000  0.00000    30
2.4.9-e.35smp                  10   4096   64    3.42 12.30%     0.418      840.21   0.00000  0.00000    28

my actual configuration is that:
[root at server1 ttcp]# drbdsetup /dev/nb0 show
Lower device: 08:12   (/dev/sda12)
Disk options:
Local address: 192.168.7.61:7788
Remote address: 192.168.7.51:7788
Wire protocol: A
Net options:
 timeout = 6.0 sec
 tl-size = 1048576
 connect-int = 10 sec
 ping-int = 10 sec
 sndbuf-size = 131070
 sync-min = 5120 KB/sec
 sync-max = 614400 KB/sec
 sync-nice = 10



the loose of write rate is too high for the programs used on these servers...
so can you tell me if my configuration is good??
and how to have better troughput?

thanks.



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