[DRBD-user] deadlock? NFS export DRBD on loop device on tmpfs

[HIROSE, Masaaki]

Hello,

I want memory storage NFS server, so using NFS server that export XFS
on DRBD on loop device on tmpfs.

This system looks like working well, but sometimes load average
increase too high (up to 20) suddenly and system is hung up.

[question]
1 Someone (on Internet) say that DRBD on loop device cause
  deadlock. Is it true?

2 What mean "top of loop device" on DRBD wiki page? loop block device?
  or network loop device?
    DataRedundancyByDrbd / Some Do's and Don'ts
    <URL:http://wiki.linux-ha.org/DataRedundancyByDrbd#head-25da1eb596fac86b9b39073f3a9566007cc6a505>

3 Does DRBD work well on loop device on tmpfs? Is there a possibility
  of deadlock or serious problem?

    mkdir /dev/memfs/0
    mount -t tmpfs -o size=1024M     none /dev/memfs/0
    dd if=/dev/zero of=/dev/memfs/0/img
    losetup /dev/loop0 /dev/memfs/0/img

    in drbd.conf
      on foo {
        device    /dev/drbd0;
        disk      /dev/loop0;
        adress    ...
        meta-disk internal;
      }

[environment]
distribution: Debian 3.1 Sarge
      kernel: 2.6.12.2 (vanilla) (stack size is 8KB)
        drbd: 0.7.11
  nfs-server: 1.0.6-3.1 (debian package)
    mkfs.xfs: 2.6.20-1 (debian package)


-- 
HIROSE, Masaaki