[DRBD-user] Problems after upgrade 8.2.0 to 8.3.0

John Du jjohndu at gmail.com
Fri Jan 30 20:34:22 CET 2009


Hi,

I upgraded DRBD 8.2.0 to 8.3.0.  The upgrade went smoothly.  However, 
the upgraded version is very slow and the system load is near 100.  
Before the upgrade the load never exceeded 1. 

The DRBD worker thread runs into "un-interruptible state" very often for 
long time.

iostat shows:

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.52    0.00    0.57    1.47    0.00   97.44

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sdb              31.02       548.36       668.39   27950963   34068995
drbd1            87.19        99.38       648.63    5065610   33061496

sdb is the underlying storage, a SAN partition of 1.2 TB.

Note that the read speed for sdb is 548 but for drbd1 99.  The write 
speeds for sdb and drbd1 are about the same.  Note the numbers of blocks 
read for sdb and drbd1 are very different. 

top shows:

Tasks:   1 total,   0 running,   1 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.2%us,  0.2%sy,  0.0%ni, 98.9%id,  0.7%wa,  0.0%hi,  0.0%si,  
0.0%st
Mem:   8175372k total,  8120248k used,    55124k free,   849224k buffers
Swap:  2031608k total,        0k used,  2031608k free,  4206700k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 5507 root        15   0     0        0       0      D    0  0.0   
0:29.36   drbd1_worker

Here is the background information

OS: Linux 2.6.18-8.1.15.el5 #1 SMP Thu Oct 4 04:06:39 EDT 2007 x86_64 
x86_64 x86_64 GNU/Linux

The primary DRBD is not connected to the secondary.

DRBD configuration:

global {
     usage-count      no;
  }

common {

  net {
     sndbuf-size     512k;
     timeout           60;
     connect-int       10;
     ping-int          10;
     max-buffers     2048;
     max-epoch-size  2048;
  }

resource drbd0 {
  protocol A;

  startup {
    wfc-timeout  30;

    degr-wfc-timeout 120;    # 2 minutes.
  }

 on host1 {
    device    /dev/drbd1;
    disk      /dev/sdb1;
    address   10.100.2.232:7789;
    meta-disk  internal;
  }

  on host2 {
    device    /dev/drbd1;
    disk      /dev/sdb1;
    address   10.101.152.36:7789;
    meta-disk  internal;
  }
}


My questions are:

1.. Does DRBD 8.3 re-organize the data on disk after the upgrade making 
the IO on drbd1 slow now and it will return to normal after it is done?

2. Can I rollback to 8.2.0 while investigating the cause of the 
slowness?  Does 8.3.0 make any changes that 8.2.0 does not rcognize?

3. What else can I do to improve the performance to a level close to 
what it was before the upgrade?

Your help is greatly appreciated.

John



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