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Re: [fuse-devel] pseudo-symlinks
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From: Franco B. <fr...@ro...> - 2004-10-28 10:39:16
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On Thu, 2004-10-28 at 18:25, Alex Martin wrote: > > > > I'm doing exactly the same thing but without trying to hide the > > symlinks. We have 26TB of data appearing as a single FUSE partition. > > > > Doesn't this confuse some user apps? No, anything that accesses files on the FUSE system thinks it's accessing a real file, the symlinks are never advertised. Eg. $ ls /3d/003/dva/vel.west -rw-r--r-- 1 3d 3284752 Oct 15 16:22 /3d/003/dva/vel.west $ file /3d/003/dva/vel.west /3d/003/dva/vel.west: ASCII text $ stat /3d/003/dva/vel.west File: "/3d/003/dva/vel.west" Size: 3284752 Blocks: 6424 IO Block: 4096 Regular File Device: 2ch/44d Inode: 15427 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 201/ 3d) Gid: ( 200/ prod) Access: Thu Oct 28 18:29:12 2004 Modify: Fri Oct 15 16:22:25 2004 Change: Fri Oct 15 16:22:25 2004 $ getfattr -n realpath /3d/003/dva/vel.west getfattr: Removing leading '/' from absolute path names # file: 3d/003/dva/vel.west realpath="/data25/3d/003/dva/vel.west" > > > > What I did was to have a separate metadata filesystem to hold all the > > links, I then dereference any pseudo path and open the real file. > > > > Filesystem Size Used Avail Use% Mounted on > > metadata/3d 26T 20T 7.2T 73% /3d > > > > > > The one big problem we have is with locking.... > > > > Yes, my current (simple) test setup also has the metadata on a shared fs... > I know it won't scale well (though it is possibly good enough for my > current needs). The plan is to eventually replaced this with some form > of distributed metadata daemons. We have 28 machines each with 3 FUSE systems and having a small NFS systems hold the links works fine, even under heavy load - ie seismic data processing. Maybe I wasn't clear about the locking issue, it doesn't work if you want to have more than a single machine access your pseudo system, the locking operations, lockf/fcntl don't get propagated to the FUSE application. |