[DRBD-user] 2.5TB DRBD disk on DRBD 0.7.2

Ian Samuel ian at MrZesty.net
Mon Aug 30 22:57:54 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.


I tried today to set up DRBD over a software-striped disk set (2 x 1.25 TB) 
for a total DRBD drive of 2.5TB.

Unfortunatley, although the source code for v0.7.2 mentions a maximum size of 
3.8TB - the size reported back by DRBD as only 310 GB instead.

I can mount and use the /dev/md5 device with reiserfs (I have enabled >2TB 
filesystem support in the kernel), it is only when I try to layer DRBD over 
top that I have a problem with this size of device.

I am using another 50GB drbd parition on the same systems and that works fine, 
and using only 1 disk (1.25GB) also works fine.

Kernel is, with DRBD 0.7.2 on Debian sarge.

Is it unrealistic to use a single DRBD device this large?   I am hoping it is 
a simple 32-bit int overflow.

Your help is appreciated.  Thanks!


resource nas {
  protocol C;
  incon-degr-cmd "halt -f";
  startup {
    wfc-timeout         0;  ## Infinite!
    degr-wfc-timeout  30;
  disk {
    on-io-error detach;
  net {
    # timeout           60;
    # connect-int       10;
    # ping-int          10;
    # max-buffers     2048;
    # max-epoch-size  2048;
  syncer {
    rate   100M;
    group   1;

  on back01 {
    device      /dev/drbd1;
    disk        /dev/md5;
    meta-disk   internal;

  on back02 {
    device     /dev/drbd1;
    disk       /dev/md5;
    meta-disk  internal;

Ian Samuel, B.Sc.
Sr. Linux System Administrator

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