(Illustration by Gaich Muramatsu)
G'day, I am in the process of setting up a _home_ fileserver with twin 80-gig disks (RAID-1 mirrored) and am looking for a distributed filesystem which will permit replication of some of my data (onto smaller ~40 gig drives I already have), scalability (up to the 200+ gig range) and single namespace across my network (mostly 100baseT linux boxes but also some Windoze and one colocated server across an untrusted WAN). I thought that CODA was the answer but it seems that it does not scale to that extent (Ref: some postings in 1999 and one or two in this list in early 2002). The documentation says the RVM metadata needs to be 4% of the total shared size and it needs to be backed by virtual memory for that same quantity. So for an 80 gig server that would be 3.2 gigs of RVM metadata, but does it really need 3.2 gigs of main memory and/or 3.2 gigs of swap space? My server has only 512 megs of main memory, soon 1024. Perhaps the question is moot, I think somebody said that 80 gigs was about the absolute maximum possible on the i386 architecture. Is any work being done on making CODA scale more? I have spent many hours slaving over a google search window and investigating distributed filesystems for linux. At the moment the most appropriate choice for any replicated data seems to be Inter-Mezzo because it uses a real filesystem as a base (and a real or virtual filesystem on the client). However I can't replicate 80+ gigs on every client, so the LAN-connected clients may well end up mounting the large filesystem using NFS. It's ugly, and I'm not sure how well I can mix Inter-Mezzo and NFS. What would be nice is a transparent filesystem or union filesystem so that I can acquire data in different ways and put it all together into one namespace which never has to change (just gets bigger) but I think that linux doesn't have a union filesystem, and if it did, it's not clear how that would be distributed. Does anybody have suggestions for a product, patch or architecture which I haven't considered here? Nick.Received on 2002-08-21 03:14:18