[DRBD-user] [Fwd: Re: [Linux-HA] heartbeat 2.0.8: lockups]kerneloops

Ross S. W. Walker rwalker at medallion.com
Wed Feb 21 23:16:31 CET 2007

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


> -----Original Message-----
> From: drbd-user-bounces at lists.linbit.com 
> [mailto:drbd-user-bounces at lists.linbit.com] On Behalf Of Ross 
> S. W. Walker
> Sent: Wednesday, February 21, 2007 5:14 PM
> To: Gerry Reno
> Cc: drbd-user at lists.linbit.com
> Subject: RE: [DRBD-user] [Fwd: Re: [Linux-HA] heartbeat 
> 2.0.8: lockups]kerneloops
> 
> > -----Original Message-----
> > From: Gerry Reno [mailto:greno at verizon.net] 
> > Sent: Wednesday, February 21, 2007 5:07 PM
> > To: Ross S. W. Walker
> > Cc: drbd-user at lists.linbit.com
> > Subject: Re: [DRBD-user] [Fwd: Re: [Linux-HA] heartbeat 
> > 2.0.8: lockups] kerneloops
> > 
> > 
> > > <snip>
> > >
> > > Are you per-chance doing "internal" storage of the 
> > meta-data on these
> > > RAID-1 arrays?
> > >
> > > -Ross
> > >
> > >   
> > Ross,
> > The DRBD metadata is stored in a separate logical volume on 
> > the RAID-1 
> > arrays.
> 
> There is a known bug in the current implementation of MD raid,
> specifically for raid-1 based arrays. The current MD code fails to
> preserve the BIO_RW_BARRIER flag on cloned bios.

Ooops I meant BIO_RW_SYNC flag.

> What this translates to in DRBD is severe performance penalties and
> possible meta-data integrity issues for meta-data stored on MD raid-1
> volumes.
> 
> Please use an alternate location for your meta-data then an 
> MD RAID-1. I
> recommend hardware raid, or LVM-mirror, or standalone disk.
> 

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