On 2/1/2017 5:08 AM, Richter, Michael wrote: > Hi, > > we are using OpenAFS for the home drive. /home/users is a symlink to > the AFS path with all the home shares. The users home is for example > /home/users/username. > > The users only have 1 GB of space available in that share. It often > happens that the quota is reached and they are unable to login. Ubuntu > doesn’t give a meaningful error message. I think, Ubuntu doesn’t know > what’s the problem, because it sees only “/” as mountpoint, which has > enough free space available.
The OpenAFS Unix cache manager exposes AFS mount points as directories not as symlinks and not as mount points. From the perspective of applications all of /afs is a single device consisting of every AFS volume in the world. In addition, while the file server offers the RXAFS_GetVolumeStatus RPC which returns . the size of the partition . the amount of free space on the partition . the size of the volume quota (if any) . the remaining free volume quota (if any) the OpenAFS Unix cache manager never queries it. As a result, the application only finds out that partition is full or the quota exceeded during the close() system call. If the quota is 2MB and an application opens a file and writes 100MB and then closes the file without checking the error code, the data is lost and the application believes the data was written to the file server successfully. As others have indicated, this is not how the Windows cache manager works. The Windows cache manager is aware of how much free space the volume has and returns an error to the application as soon as the free space reaches zero. In addition, because the Windows cache manager exposes each AFS volume as a separate device, it is possible to: . report some volumes as readonly and others as read/write . return accurate volume size and free space info for each path . report accurate quota information for each path . return out of space and out of quota errors on one path without causing the VFS to report those same errors on other paths David Howell's kafs, the Linux in-tree AFS client, behaves in a manner similar to the Windows client. https://www.infradead.org/~dhowells/kafs/ kafs requires testing, it requires that end user organizations inform their preferred Linux distributions that building and distributing kafs is important. AuriStor, Inc. supports David Howells' development of kafs. Others should as well. Jeffrey Altman
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