When git annex does fsck on (for example) a GPG-encrypted special directory remote, it first transfers the whole file into .git/annex/tmp directory. If your annex is on an SSD, it's a good idea to make .git/annex/tmp a symlink to say /var/tmp so SSD isn't worn down. This actually may be a better default.
fsck
on the (encrypted) remote itself, as it would avoid to clutter either the network or the tmpdir. However, that requires some changes in git-annex's backend. Indeed it would no longer be enough to store a single digest per (plain) file: a new digest needs to be stored for each encrypted copy. It is not necessarily a big deal, but the backend would need to be reorganized carefully.If .git/annex/tmp is a symlink to another fs, then adding doesn't work:
It looks like it would be good to have two types of tmp directories here, one for adding, another one for verifying (and that one could be redirected off SSD).