server down, but its back up.. what should be done ?

[Evert|Rooftop]

Dear List,

One of our servers went down and it was marked by the other servers as
'invalid', so it won't use it anymore..

However, it's back up now.. will memcache (PHP PECL) automatically retry
after a while or should apache be started on all those machines..

It also made me wonder about something else, when a server is down..
will the hash thats used to determine the target server be adjusted to
just use the other servers? Or will the hashes that would have targeted
the server thats down be re-distributed?

Thanks,
Evert