On Sat, Mar 31, 2012 at 10:43:02PM +0200, Corin Langosch wrote: > Hi, > > I'm looking for a distributed, fault-tolerant network storage system which > exposes block devices (not filesystems) on the clients. Matching my > requirements I only found ceph's rdb, but it's still very experimental as far > as I know. So I'm thinking about implementing the system myself using nbd and > the design of moosefs, http://www.moosefs.org/, which is quite simple (the > single point of failure master server is ok for me). > > But there's a question left: I read nbd can easily be deadlocked when not > properly dealt with memory requests: > > > when the system is short of memory, it tries to write back dirty pages. So > the nbd client asks the nbd server to write back data, but as nbd-server > is > a userland process, it may require creating dirty pages to fullfill the > request.
You can only hit that specific deadlock if you run nbd-client and nbd-server on the same machine. If you don't, there's still a chance for another deadlock (if you put your swapspace on the NBD device), but the chance of that happening is significantly lower. -- The volume of a pizza of thickness a and radius z can be described by the following formula: pi zz a ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Nbd-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nbd-general
