When re-installing, be careful not to wipe your storage pool drives (better you disconnect them while you re-install).
After re-installing, just re-do what you did to setup your storage pool initially:
1. Mount the drives where they were mounted before
2. Go on the Amahi dashboard, Storage Pool page, and select the drives that were in your storage pool before
3. Go in the Shares page, and select 'Uses Pool', and the correct number of extra copies, for all the shares which are part of your storage pool.
(You might need to re-create some non-default shares, if you had any.)
At that point, you should be able to see your files in your pooled shares.
If some files are missing, it might be because your drives changed name, and thus mount point (if you used hda-diskmount to mount them in /var/hda/files/drives/...) i.e. what was before known as /var/hda/files/drives/sdb1 might have become /var/hda/files/drives/sdc1.
If all files are missing, it's probably that your shares were on the partition that you wiped, and thus, all symlinks to the file copies in your storage pool are now gone.
To fix that, wait for the nightly Greyhole check to run, or run it manually from a Terminal:
Greyhole will then find the file copies on your pooled drives, and re-create the necessary symlinks in your shares.
To see when fsck is done:
Wait for that to say something like 'Sleeping...' every 10 seconds, which will mean it's done with fsck, and is now waiting for something to do.