2015-04-13 15:37 GMT+02:00 Benjamin Coddington <bcodding@xxxxxxxxxx>: > Hi Baptiste, > > On Sat, 11 Apr 2015, Prunk Dump wrote: > >> Hello NFS team, >> >> On my network I share my users' home directories from a kerberized NFS4 server. >> >> I would like to split this shared filesystem tree on 3 servers to >> reduce server loading and increase storage capacity. I don't want file >> replication, just distribution. >> >> On this link : >> >> http://www.ibm.com/developerworks/library/l-generic-nfs-mount/ >> >> I can read that "NFS version 4 provides a pseudo-tree mechanism that >> enables a single mount of all NFSv4 exported entries" >> >> I can't find documentation of this feature. Is it works on multiple >> servers ? Is this possible to mount multiple NFS4 shares on a same >> mount point without using a special file system like Unionfs or >> Glusterfs ? > > I believe they are talking about NFSv4 referrals, and it is possible > provided your server supports the fs_locations attribute. > >> What is the preferred way of network administrators to distribute >> their users' home directories through NFS4 ? > > One method I've used for an installation with < 100k users was based on > a simple automount map and using symlinks to hash out users' home > directories on a "lookup" filesystem. > > There's a "lookup" filesystem automounted on every client here: > > /users > > with directories like /users/b/c/ and /users/f/o. Each directory contains > symlinks to users' real home directory location, for example: > > /users/b/c/bcodding -> /nfs/04/users/b/c/bcodding > /users/f/o/foo -> /nfs/f2/users/f/o/foo > > Users' pwnam home directories are of the predictable form: > > /users/b/c/bcodding > /users/f/o/foo > > The main file servers themselves are automounted on each client at > /nfs/<servername> as you can see in the symlink targets above. Predictable > naming conventions allow you to use autofs wildcarding for server name > matches, so you don't need to update the maps to scale. > > The lookup filesystem becomes a single point of failure, but that can be > mitigated in a few ways that are simplified by the fact that this data is > almost always RO and is very small. > > A migration of a users' home dir can become an issue if you don't have full > control of the clients, so you can avoid this by starting with a very wide > distribution of file servers and growing the filesystems over time. In this > setup, there were only a few clients that could write, so migrations were > eased by only migrating users if they didn't have open files on those > client. > > If you're using shared storage, even better. You can match server names to > block devices and script-mount them in the file servers so that deploying a > new fileserver can be done by allocating the block device and cloning the > fileserver image. > > Shared storage also provides an HA or scriptable availability solution by > allowing you to recover a file server from a known good image, or migrate > the underlying block device to a known good server. > > HTH, > Ben > >> >> Thanks, >> Baptiste. >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Thank you Benjamin ! You help me a lot ! NFSv4 referrals is exactly what I search for. I need to check if it is well supported on my Debian Wheezy servers and clients. I have approximately 1100 users and 350 computers so I need to have the possibility to move the home folders easily between my servers. If I can't get the NFS referrals working I will try with you second solution. Thank you again ! Baptiste. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
