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

[HIROSE, Masaaki]

Hello,

Thanks for reply.

Additionaly question and ask advice.

1 Why DRBD deadlock on loopback device? Does fsync() cause deadlock?

2 Is there any idea that DRBD on huge (1G-12GB) memory base device?

  NG tmpfs   - tmpfs is not block device.
  NG ramfs   - ramfs is not block device.
  NG ramdisk - too small. (up to 512MB x 16 devices?)

  NG loseup + tmpfs - cause deadlock.
  NG loseup + ramfs - cause deadlock.

  ?? LVM + many ramdisk - create big block device with join many
                          ramdisk(/dev/ramX).
  ?? MD  + many ramdisk - ditto.

  ?? other idea??



in "Re: [DRBD-user] deadlock? NFS export DRBD on loop device on tmpfs"
   <20050804053619.GA13037 at barkeeper1.linbit>
at Thu, 4 Aug 2005 07:36:19 +0200,
   Lars.Ellenberg at linbit.com wrote:

> > 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?
> 
> yes.
> 
> > 
> > 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>
> 
> from the context, it should be clear that loop block dev is meant.
> 
> > 3 Does DRBD work well on loop device on tmpfs?
> 
> no
> 
> > Is there a possibility of deadlock or serious problem?
> 
> yes

-- 
HIROSE, Masaaki