thanks, Sergey!
On Fri, Jul 19, 2013 at 11:38 AM, Sergey Maslyakov <[email protected]> wrote: > Alexander, > > I cannot speak to that intelligently. I don't know implementation and > design details well enough. However, a snapshot of this kind, if it is > produced by ZooKeeperServer.takeSnapshot() method, should contain not just > the DataTree content but the sessions too. I am not sure if this covers > ephemeral nodes though but I am pretty sure this is way Zookeeper server > takes snapshots driven by the transaction count. > > > Regards, > /Sergey > > > On Fri, Jul 19, 2013 at 1:26 PM, Alexander Shraer <[email protected]> wrote: > >> Sergey, >> >> Can you explain what happens with ephemeral nodes during snapshot and >> restore ? >> >> Thanks, >> Alex >> >> On Fri, Jul 19, 2013 at 11:21 AM, Sergey Maslyakov <[email protected]> >> wrote: >> > Jordan, >> > >> > It depends on the use case. Some use cases deal with 99% or more of >> static >> > non-ephemeral nodes. And this is why the Exhibitor approach does not work >> > for those use cases. >> > >> > >> > Regards, >> > /Sergey >> > >> > >> > On Fri, Jul 19, 2013 at 1:13 PM, Jordan Zimmerman < >> > [email protected]> wrote: >> > >> >> I'm a bit late to this one but I don't understand the need for complete >> >> backup of ZK data. In my experience, 99% of ZNodes are ephemeral. >> >> Therefore, it would be wrong to restore those nodes. In a disaster, the >> >> connection sessions would expire and you would not want ephemeral nodes >> >> restored. This is why in Exhibitor I took the approach of selective >> restore. >> >> >> >> -Jordan >> >> >> >> On Jul 19, 2013, at 11:00 AM, jack ma <[email protected]> wrote: >> >> >> >> > I asked those question in the thread >> >> > >> >> >> http://mail-archives.apache.org/mod_mbox/zookeeper-user/201307.mbox/%3cCAB+cfdwhOV0JfB04=MpO_+i-4ou=VbL=eg2xs557+j+698j...@mail.gmail.com%3e >> >> , >> >> > but there is no response for that. >> >> > >> >> > So I posted those questions again here, hopefully I could get helps >> >> > from the community. >> >> > >> >> > I want to make sure I am fully understanding the procedures of >> zookeeper >> >> > backup and disaster recovery: >> >> > >> >> > For the backup procedures at zookeeper assemble: >> >> > (1) Login to any host which state is "Serving" >> >> > Question: >> >> > Do I have to login to leader node, or any node is ok? >> >> > (2) Copy latest snapshot file and transaction log from version-2 >> >> directory. >> >> > Question: >> >> > How to make sure we do not copy corrupt files if the >> >> > snapshot/transaction log is in the middle of update? Do we have to >> >> shutdown >> >> > the node to make the copy? >> >> > besides the transaction log and snapshot, do we have >> to >> >> > copy other files such as the ecoch files >> >> > >> >> > For the disaster recovery procedures at zookeeper assemble: >> >> > (1) recreate the machines for the zookeeper ensemble >> >> > (2) copy snapshot/transaction log we backed up into the zookeeper >> >> > dataDir\version-2 and logDir\version2. >> >> > Question: >> >> > Do we have to copy the epoch files? >> >> > Do we have to copy snapshot/transaction log backed up >> to >> >> > all the zookeeper node, or just the first node we starts? >> >> > >> >> > Appreciate your time and help. >> >> > Jack >> >> >> >> >>
