Re: host clocks

2011-07-25 Thread Peter Schuller
> As I understand it, this will not quarantee that they are millisecond > accurate which is what you need for Cassandra to use the correct commit. > We've seen problems in production and had to rearchitect parts of the system > due to this even though all servers are NTP synched. It does not ma

Re: host clocks

2011-07-25 Thread Paul Loy
we don't have those guarantees on EC2. Networks can fluctuate wildly. On Mon, Jul 25, 2011 at 2:00 PM, zGreenfelder wrote: > > > On Mon, Jul 25, 2011 at 8:51 AM, Paul Loy wrote: > >> As I understand it, this will not quarantee that they are millisecond >> accurate which is what you need for Cass

Re: host clocks

2011-07-25 Thread zGreenfelder
On Mon, Jul 25, 2011 at 8:51 AM, Paul Loy wrote: > As I understand it, this will not quarantee that they are millisecond > accurate which is what you need for Cassandra to use the correct commit. > We've seen problems in production and had to rearchitect parts of the system > due to this even tho

Re: host clocks

2011-07-25 Thread Paul Loy
xt problem, if you have more than one client... >> >> >> On Mon, Jul 25, 2011 at 5:25 AM, Edward Capriolo >> wrote: >> >>> You should always sync your host clocks. Clients provide timestamp but >>> for the server gc_grace and ttl columns can have issues

Re: host clocks

2011-07-25 Thread Sooraj S
>> You should always sync your host clocks. Clients provide timestamp but for >> the server gc_grace and ttl columns can have issues if server clocks are not >> correct. >> >> On Sunday, July 24, 2011, 魏金仙 wrote: >> > hi all, >> >I'm launchi

Re: host clocks

2011-07-25 Thread Paul Loy
And I guess there's the next problem, if you have more than one client... On Mon, Jul 25, 2011 at 5:25 AM, Edward Capriolo wrote: > You should always sync your host clocks. Clients provide timestamp but for > the server gc_grace and ttl columns can have issues if server clocks are no

Re: host clocks

2011-07-24 Thread Edward Capriolo
You should always sync your host clocks. Clients provide timestamp but for the server gc_grace and ttl columns can have issues if server clocks are not correct. On Sunday, July 24, 2011, 魏金仙 wrote: > hi all, >I'm launching a cassandra cluster with 30 nodes. I wonder whether the in

host clocks

2011-07-24 Thread 魏金仙
hi all, I'm launching a cassandra cluster with 30 nodes. I wonder whether the inconsistency of host clocks will influence the performance of cluster. Thanks!