>-----Original Message----- >From: Florian Haas [mailto:[email protected]] >Sent: Sunday, October 07, 2012 5:46 PM >To: Dan Barker >Cc: drbd List >Subject: Re: [DRBD-user] Does oversize disk hurt anything? > >On Sun, Oct 7, 2012 at 2:20 PM, Dan Barker <[email protected]> wrote: >>>Well if you had created a partition (/dev/sdc1) rather than use the full >>>disk (/dev/sdc), then you could have set up that partition to match the size >>>of the disk on your primary. >> >> Partition. Great idea. If I had thought of that, I'd have bought only one >> new 500G disk instead of two. Thanks for the hint. 1T disks cost the same as >> 500G these days. > >The physical device sizes differing isn't a problem at all; DRBD will just >select the smaller size of the two. I know drbd is just using the outside 500G of the oversize disk. It's just that the metadata is in near the hub. A partition would have placed it mid-disk but I didn't think of that. > >>>Why? Your cluster manager (typically Pacemaker) should take care of that for >>>you. >> >> No cluster manager, no NA. Easy manual failover. This is a lab environment >> and HA is not really needed. The users of drbd storage are ESXi hosts. To >> "take" the primary server off line I: >> DrbdR0: drbdadm primary all (allow dual primaries is on) >> DrbdR0: start iet >> ESXi (all): verify all four paths to both drbd are online > >We may have had this discussion before, but: >http://fghaas.wordpress.com/2011/11/29/dual-primary-drbd-iscsi-and-multipath-dont-do-that/ > >> Thanks for the help. > >Pleasure. > >Cheers, >Florian
Of course I've been following the dont-do-that threads. I've been down that path several times. It works great for a while and then doesn't<g>. But that was a couple of years ago. What I am currently doing is different; the exposure is very brief, if at all. When the second DRBD publishes its iSCSI paths, ESXi discovers them but continues to use the original path for all I/O. It's not concurrent multipath. Only when the original path dies (when I stop iet on the "primary" drbd) does ESXi switch to active I/O on the "other" path. I think your fears are about simultaneous dual-access, not about what I'm doing. I don't think I'd recommend anyone else do it this way, it's just the way I'm doing it with the hardware laying around. Thanks for the feedback. Here's some feedback for you: drbd is Great! Thanks for making it available. Best wishes for you at Hastexo. Dan _______________________________________________ drbd-user mailing list [email protected] http://lists.linbit.com/mailman/listinfo/drbd-user
