-Re: help! some questions about zk
Thawan Kooburat 2013-10-21, 23:53
(2) You can lose a committed data if have more failure than what the
quorum is configured to support (eg. losing 3 out of 5 hosts)
On 10/21/13 4:48 PM, "Alexander Shraer" <[EMAIL PROTECTED]> wrote:
>(1) Zab is an atomic broadcast protocol, it satisfies strong ordering
>properties. Check out the paper:
>Its used to propagate updates in the same order to all the ZooKeeper
>servers. The provided consistency in ZooKeeper is basically sequential
>real-time-order on writes. This is strong, although not linearizable
>(its possible that you read from a server that has stale data).
>If you use the sync call before a read, ZooKeeper provides
>ilnearizability for sync+read and write operations (this is true with
>certain timing assumption made in ZooKeeper for efficiency).
>(2) No, only a suffix of uncommitted operations can disappear.
>Operations acked by a quorum never dissappear.
>(3) For read operations the server responds immediately using local
>state. For writes it responds after a quorum acked the update.
>On Mon, Oct 21, 2013 at 1:47 AM, 聂安 <[EMAIL PROTECTED]> wrote:
>> hi all,
>> About zk, I got some questions bothered me for one week, which can be
>>described as follows:
>> (1) Does zab guarantee a strong consistency?
>> (2) Could those committed proposals on new-elected-followers be deleted
>>when initially synced?
>> (3) When does the server in zk respond to the client? After commiting
>> thank you！