Re: [infinispan-dev] Proposal: ISPN-1394 Manual rehashing in 5.2

From: "Dan Berindei" <dan.berindei(a)gmail.com&gt; >> numOwners==2 is and will very likely remain the most common case, >> particularly for small clusters. >> >> But if we have two sites, it makes sense to configure 2 owners per >> site. If only one node goes down, the surviving owner will supply >> state to the new owner. If both nodes go down, the new owners will >> fetch the data from the other site. So while 2 nodes going down >> will >> be quite costly, it should be infrequent enough that it's worth >> optimizing for the more frequent "1 node goes down and than comes >> back >> up" case. >> > Agreed; this mixed batching (leaves with joins) makes sense for > non-site clusters as well. > Yup, even with numOwners == 2 you could say that 2 nodes dying in 1 minute is highly improbable. So you can delay rehashes triggered by leaves by 1 minute just in case the node comes back up. >> > For total shutdown, I guess we can use other means that rehash, >> > e.g. a specific command that would disable it and start flushing >> > to the store. >> > >> >> I think just stopping the cache is enough to get it to flush data >> to >> the store with passivation enabled. > ATM, wouldn't the shutdown of a cluster of servers trigger a rehash > storm? > Right. I was commenting only on the cache store part, which should be completely orthogonal to graceful shutdown. I think we need a mechanism to better handle partial cluster shutdown, and that mechanism can be used for full shutdown as well.