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: Lars Ellenberg [mailto:lars.ellenberg at linbit.com] > Sent: Wednesday, May 23, 2007 12:27 PM > To: Ross S. W. Walker > Cc: drbd-user at lists.linbit.com > Subject: Re: [DRBD-user] DRBD 0.7.23 and MD corruption > > On Wed, May 23, 2007 at 12:16:25PM -0400, Ross S. W. Walker wrote: > > Lars, et al, > > > > I was wondering if a block storage device, which could > exist on an MD, > > were to be fully utilized before it was incorporated into a drbd > > replication scheme would it also suffer from corruption. > > > > Why I ask, is that I have a bunch of volumes used as iSCSI targets > > that I am planning on replicating in the future, but are in > production > > today and wanted to know if it is safe to create replicas of these, > > using a separate LV for meta-data? > > if you have the drbd meta data on a separate lv, > DRBD is completely "transparent", > comparable to a dm-linear mapping over the full device. That is what I figured. > so it "should just work", > and it does so for us, all the time. > > but, you know, murphy and "shit happens" ... > and the issue with the "READA failing without error on MD raid5", > mentioned earlier in this thread is a real one. > dm-crypt has suffered from it, and so would drbd, probably, > when stacked directly on a md raid5 array. Yes, there seems to always be something creeping up from MD/DM... I remember the performance issue with meta-data on raid1 and barriers not being passed down. > we will double check and realease a workaround. > > note that typical usage is unaffected, though. > [md is a pv, and drbd resides on an lv, so on dm-linear] I think the safest thing is to use hardware raid for important data. Another thing, is there any plans to implement a many-to-many replication topology with DRBD say utilizing multicasting? -Ross ______________________________________________________________________ This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender and permanently delete the original and any copy or printout thereof.