Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 2/15/07, Greg Freemyer <greg.freemyer at gmail.com> wrote: <snip> > As to: > > "You can stack DRBD on top of md, md on top of DRBD is nonsense, however". > > I still don't know why that is true in a active-passive setup. It > seems totally logical to me to stack md raid0 above drbd raid1 in a > active-passive setup, but that may be different thread. > I was thinking some more about this and I believe the issue is with ordered writes. IIRC, drbd provides 3 modes of operation related to ordered writes. By stacking a raid layer above drbd you break its ability to control ordered writes because no single instance of drbd sees the whole picture. I'm not a drbd expert, but if you look at the 3 modes you can probably see why it would be bad even in a active passive setting. Greg -- Greg Freemyer The Norcross Group Forensics for the 21st Century