Messages in this thread | | | Date | Sun, 12 Aug 2007 19:03:44 +0200 (CEST) | From | Jan Engelhardt <> | Subject | Re: [RFD] Layering: Use-Case Composers (was: DRBD - what is it, anyways? [compare with e.g. NBD + MD raid]) |
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On Aug 12 2007 09:39, david@lang.hm wrote: > > now, I am not an expert on either option, but three are a couple things that I > would question about the DRDB+MD option > > 1. when the remote machine is down, how does MD deal with it for reads and > writes?
I suppose it kicks the drive and you'd have to re-add it by hand unless done by a cronjob.
> 2. MD over local drive will alternate reads between mirrors (or so I've been > told), doing so over the network is wrong.
Certainly. In which case you set "write_mostly" (or even write_only, not sure of its name) on the raid component that is nbd.
> 3. when writing, will MD wait for the network I/O to get the data saved on the > backup before returning from the syscall? or can it sync the data out lazily
Can't answer this one - ask Neil :)
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