[DRBD-user] Speed Sync seems to be limited on gigabit ethernet
mlist at itspecialist.it
Wed Jun 20 16:51:30 CEST 2007
thanks for answers.
Siim Vahtre wrote:
> On Wed, 20 Jun 2007, Marcello Lupo wrote:
>> If i force the sync of the partitions to drbd with invalidate_remote
>> it do not go over 12 Mb/sec.
> This doesn't seem normal.
> Some obligatory questions:
> * Are you sure you actually have working fullduplex Gbit link? (check
> with ethtool)
Settings for eth1:
Supported ports: [ MII ]
Supported link modes: 10baseT/Half 10baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
Advertised auto-negotiation: Yes
Port: Twisted Pair
Supports Wake-on: g
Current message level: 0x000000ff (255)
Link detected: yes
> * Are you sure you actually can write to your disks faster than
> 12Mbytes/sec? (try with benchmarking tool that comes with drbd 'dm.c')
I tried to copy with scp from one machine to the other a 4GB file and it
went at ~40Mb/s.
Tool you said dm.c the documentation says that is untouched from version
0.6 and not working currently with 0.7 version.
SOme times in cat /proc/drbd i see some peak of speed around 18/20
Mb/sec but it is very rare. the average is everytime around 14/15 Mb/sec.
Now i tried with bonnie++ and this is the result
Version @version@ ------Sequential Output------ --Sequential
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
host0 4G 40987 99 85422 33 45074 11 53951 99 120726 15
host0 4G 41007 99 88090 34 44630 11 53664 99 122682 16
------Sequential Create------ --------Random
-Create-- --Read--- -Delete-- -Create-- --Read---
files:max:min /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
host0 16 17641 99 +++++ +++ 16958 99 19706 100 +++++ +++
host0 16 15767 76 +++++ +++ 17099 99 19778 99 +++++ +++
> * Are you sure nothing else is writing to disks at the same time?
Yes the servers are not used at the moment. I'm just making all
preinstall tests of speed and so on before install.
>> i tried with rate option to 50M,40M,30M and it is the same.
> * Did you drbdadm adjust after changing config?
I made drbd completely stop and start to be sure all the times i changed
> * Have you searched the mailing-list archives? I think I have seen
> several questions like yours, maybe someone has already solved problem
> like this.
I searched for something but found nothing that was usefull to me.. May
be i didn't searched so well.
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