On Sat, Apr 05, 2008 at 09:52:55AM +1100, Crossfire wrote: > I've just spent some time quickly researching this to no real satisfaction. > > What I'm looking for is a way to do real-time hot-replication of a whole > filesystem or filesystem tree over 2 nodes (and strictly 2 nodes) > without STOMITH[1]. > > The scenario is I have two identical systems with local (software) > RAID1. They will be tethered onto their internet feed via ethernet, and > can optionally be tethered to each other via Gig. > > I want to be able to set it up so /home (and maybe other filesystems) > are replicated from one to the other, in both directions, in real time > so they can run in an all-hot redundant cluster. > > The environment should be mostly read-oriented, so I can live with > write-latent solutions as long as they handle the race/collision > gracefully (preferably by actually detecting and reporting it if they > can't avoid it). > > The options I've investigated so far: > > * Lustre (MDS requirements[2] make this not an option) > * GlobalFS (STOMITH requirements make this not an option. Oriented > towards shared media too, which I am not using) > * tsync (Naive concurrent operation model, but otherwise viable) > * MogileFS (not quite what I was looking for, but none the less useful). > * OpenAFS (read-only replication only, loss of the node hosting the > write volume still renders the volume unwritable). > > Is anybody aware of any other options that I've missed? I think once you ask for no STOMITH and also read/write access from more than one location, you have made it really hard for yourself. Unless you go to something NFS.
Lustre doesn't really met you requirements. its more for file striping and speed then for HA if 1 can be readonly then you could setup a raid 1 with one device being a network block device > > C. > > [1] "Shoot The Other Machine In The Head" - the ability for any node to > forcibly powerdown any other node believed to be malfunctioning. > [2] Single instance MDS only, only clusterable through shared storage. > d'oh. > [3] People suggesting rsync will be taken out back and shot for not > reading the requirements. > -- > SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ > Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html > -- "I also understand how tender the free enterprise system can be." - George W. Bush 07/08/2002 White House press conference, Washington, D.C.
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