[DRBD-user] Standalone drbd Server without secondary is terribly slow

[Christoph Adomeit]

Hi,

I have setup a new node to be a drbd primary.

Later on I will have a secondary but that hardware is not even 
delivered to us. However, I wanted to finish the final configuration 
of the primary node now.

So I have setup only a primary drbd setup of lvm above drbd, which works
good. Filtered the disk sdb in lvm.conf for not getting
lvm to use /dev/sdb instead of /dev/drbd0. Drbd is in standalone mode now.

However, drbd is terribly slow, that server makes 300 MB/s writes
on local disk but on top of drbd only 3 MB/s.

/proc/drbd says:
version: 8.3.0 (api:88/proto:86-89)
GIT-hash: 9ba8b93e24d842f0dd3fb1f9b90e8348ddb95829 build by root at san01,
2009-02-09 16:18:25
 0: cs:StandAlone ro:Primary/Unknown ds:UpToDate/DUnknown   r---
     ns:0 nr:0 dw:1350856 dr:1084 al:926 bm:669 lo:3 pe:0 ua:0 ap:2 ep:1
     wo:b oos:5819396636

kernel 2.6.27-11-server from ubuntu, drbd 8.3 hand compiled by me.

drbd.conf: nothing special
resource san01cluster {
  protocol      B;
    startup {
    wfc-timeout 10;
    degr-wfc-timeout    20;
  }
  disk { on-io-error detach; }
  syncer {
    rate 300M;
  }

on san01 {
  device      /dev/drbd0;
  disk        /dev/sdb;
  address     10.65.1.10:7891;
  meta-disk   internal;
}
  on san02 {
  device      /dev/drbd0;
  disk        /dev/sdb;
  address     10.65.1.11:7891;
  meta-disk   internal;
}
}


root at san01:~# pvdisplay
  --- Physical volume ---
    PV Name               /dev/drbd0
    VG Name               vg0
    PV Size               5,42 TB / not usable 540,00 KB
    Allocatable           yes
    PE Size (KByte)       4096
    Total PE              1420751
    Free PE               1395151
    Allocated PE          25600
    PV UUID
    ul9Xjf-6nET-zUb2-b1my-Qb7M-02t8-Ai4CpO

lvdisplay

root at san01:~# lvdisplay
  --- Logical volume ---
    LV Name                /dev/vg0/images
    VG Name                vg0
    LV UUID                aewpzg-cMiC-cFVA-kBGi-2vMW-10Gz-LMs9Mu
    LV Write Access        read/write
    LV Status              available
    # open                 1
    LV Size                100,00 GB
    Current LE             25600
    Segments               1
    Allocation             inherit
    Read ahead sectors     auto
    - currently set to     256
    Block device           254:0


writes to /dev/vg0/images ares slow, while writes to sda1, the root
filesystem are fast, tested with bonnie++

Any idea what might be the reason for the server being so slow ?

-- 
Christoph Adomeit
GATWORKS GmbH
Reststrauch 191
41199 Moenchengladbach
Sitz: Moenchengladbach
Amtsgericht Moenchengladbach, HRB 6303
Geschaeftsfuehrer:
Christoph Adomeit, Hans Wilhelm Terstappen

Christoph.Adomeit at gatworks.de     Internetloesungen vom Feinsten
Fon. +49 2166 9149-32                      Fax. +49 2166 9149-10
-- 
Christoph Adomeit
GATWORKS GmbH
Reststrauch 191
41199 Moenchengladbach
Sitz: Moenchengladbach
Amtsgericht Moenchengladbach, HRB 6303
Geschaeftsfuehrer:
Christoph Adomeit, Hans Wilhelm Terstappen

Christoph.Adomeit at gatworks.de     Internetloesungen vom Feinsten
Fon. +49 2166 9149-32                      Fax. +49 2166 9149-10