Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
hi,
i've made some performance benchs with bonnie++ on DRBD 0.7.10-4 and DRBD 0.7.19-1.
But i don't understand some of my results.
1/ description
1.1/ Hardware description
Here are the descriptions of the 2 servers:
common description:
- Intel(R) Celeron(R) CPU 2.40GHz
- 256MB SDRAM
- network card 1Gbps
node1:
- HD IDE disk 41GB ExcelStor Technology J240
node2:
- HD IDE disk 41GB IBM IC35L060AVV207-0
The hard drive of node2 seems to be better than the node1's.
1.2/ Software description
with DRBD 0.7.10-4:
- debian stable
- kernel 2.6.8-3-686
with DRBD 0.7.19-1:
- debian testing
- kernel 2.6.15-1-686
Only bonnie++ is running on systems during the tests.
2/ DRBD's configuration
resource drbd0 {
protocol C;
incon-degr-cmd "echo '!DRBD! pri on incon-degr' | wall ; sleep 60 ; halt -f";
startup {
wfc-timeout 1;
degr-wfc-timeout 1;
}
disk {
on-io-error detach;
}
net {
max-epoch-size 8000;
max-buffers 10000;
}
syncer {
rate 150M;
group 1;
al-extents 521;
}
on node1 {
device /dev/drbd0;
disk /dev/hda4;
address 10.2.0.1:7788;
meta-disk /dev/hda3 [0];
}
on node2 {
device /dev/drbd0;
disk /dev/hda4;
address 10.2.0.2:7788;
meta-disk /dev/hda3 [0];
}
}
3/ results of test
3.1/ on node1
3.1.1/ without drbd (HD bench)
Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
node1 3G 28657 94 44144 20 22656 9 29378 85 51293 9 100.6 0
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 510 38 +++++ +++ 5329 8 516 38 +++++ +++ 2502 68
3.1.2/ with DRBD 0.7.10-4
Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
node1 3G 20698 75 23434 13 17667 9 29679 90 45123 11 93.1 0
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 324 25 +++++ +++ 856 7 331 24 +++++ +++ 722 15
3.1.3/ with DRBD 0.7.19-1
Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
node1 3G 23315 76 25195 12 17857 8 32066 86 45423 9 97.7 0
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 324 25 +++++ +++ 387 7 329 25 +++++ +++ 297 6
3.2/ on node2
3.2.1/ without drbd (HD bench)
Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
node2 3G 28951 95 34923 16 18772 8 30286 87 42595 7 113.0 0
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 552 37 +++++ +++ 5850 8 551 37 +++++ +++ 1952 56
3.2.2/ with DRBD 0.7.10-4
Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
node2 3G 18555 73 20250 15 12203 7 30021 91 30243 7 98.1 0
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 306 16 +++++ +++ 1260 2 307 16 +++++ +++ 851 19
3.2.3/ with DRBD 0.7.19-1
Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
node2 3G 21861 70 20758 10 12278 6 30462 80 30524 6 101.4 0
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 312 22 +++++ +++ 346 4 317 23 +++++ +++ 287 5
4/ Questions
4.1/ why the reading per character (Sequential Input Per Chr) with DRBD (both versions) is faster
than without DRBD ?
Is it because the node2's disk is better, the read is made on the 2 nodes and the fastest response
is used?
However I've read on the first page of the DRBD's site :"Reads are always carried out locally."
4.2/ Why do I have difference on reading between tests with and without DRBD whereas it is said on
the site that DRBD has no impact on readings?
4.3/ I've read in the drbd-announce mailinglist of May that :
"With drbd-0.7.18 on top of DRBD we got only
about 70MB/sec read performance, while with that modification
in 0.7.19 we can get the whole 320MB/sec out of DRBD as well."
The results between DRBD 0.7.10-4 and DRBD 0.7.19-1 seem a bit similary.
In which conditions, does the read performance increase like this?
4.4/ About create and delete tests (sequential and random), the performance are really decreased
when using DRBD (both versions).
Why are the performance so low ?
Especially with delete, why the result of DRBD 0.7.19-1 are worse than DRBD 0.7.10-4 and so low!
Julien WICQUART