mention symlinking the shares directory in configuration.rst

[davidsarah]

PRab looked in docs/configuration.rst​ (which is a reasonable place to look) for documentation about whether it would work to symlink the shares directory.

[marlowe]

Appropriate references

" Q8: Can there be more than one storage directory on a storage node? So if a storage server contains 3 drives without RAID, can it use all 3 for storage?

A: Not directly. Each storage server has a single "base directory" which we term $BASEDIR. The server keeps all of its shares in a subdirectory named $BASEDIR/storage/shares/. (Note that you can symlink this to whatever you want: you can keep the rest of the node's files in one place, and store all the shares somewhere else). Since there's only one such subdirectory, you can only use one filesystem per node. On the other hand, shares are stored in a set of 1024 subdirectories of that one, named $BASEDIR/storage/shares/aa/, $BASEDIR/storage/shares/ab/, etc. If you were to symlink the first third of these to one filesystem, the next third to a second filesystem, etc, (hopefully with a script!), then you'd get about 1/3rd of the shares stored on each disk. The "how much space is available" and space-reservation tools would be confused (including making the reserved_space parameter unusable), but basically everything else should work normally.

A cleaner solution would be to use LVM instead, which can combine several physical disks (or loop devices consisting of common files) to a single logical volume. This logical volume can then be mounted or symlinked to $BASEDIR/storage. This also is a more flexible solution because new disks can then be added seamlessly to the volume with LVM."

in NEWS.rst

• Storage servers now calculate their remaining space based on the filesystem containing the storage/shares/ directory. Previously they looked at the filesystem containing the storage/ directory. This allows storage/shares/, rather than storage/, to be a mount point or a symlink pointing to another filesystem. (#1384_)

[amontero]

I also remember that symlinking to "storage" parent dir threw me confusing messages (can't remember which) while testing 1.10 some time ago. Just looked the docs but in search of this particular ticket, the FAQ didn't help. I do not know much about the code, just trying to make it work.

Now so far, permission problems with the desktop user mounted drive and my Tahoe instance running as a service under another user. Still, looking how to fix it. Subscribe.

[daira]

Replying to amontero:

I also remember that symlinking to "storage" parent dir threw me confusing messages (can't remember which) while testing 1.10 some time ago.

I'm afraid that isn't enough information to reproduce. If you can reproduce this problem, please open a ticket.