Exactly.
On 23-05-2017 23:55, Gopal, Dhruva wrote: > > By that do you mean it’s like bootstrapping a node if it fails or is > shutdown and with a RF that is 2 or higher, data will get replicated > when it’s brought up? > > > > *From: *Cogumelos Maravilha <cogumelosmaravi...@sapo.pt> > *Date: *Tuesday, May 23, 2017 at 1:52 PM > *To: *"user@cassandra.apache.org" <user@cassandra.apache.org> > *Subject: *Re: EC2 instance recommendations > > > > Yes we can only reboot. > > But using rf=2 or higher it's only a node fresh restart. > > EBS is a network attached disk. Spinning disk or SSD is almost the same. > > It's better take the "risk" and use type i instances. > > Cheers. > > > > On 23-05-2017 21:39, sfesc...@gmail.com <mailto:sfesc...@gmail.com> wrote: > > I think this is overstating it. If the instance ever stops you'll > lose the data. That means if the server crashes for example, or if > Amazon decides your instance requires maintenance. > > > > On Tue, May 23, 2017 at 10:30 AM Gopal, Dhruva > <dhruva.go...@aspect.com <mailto:dhruva.go...@aspect.com>> wrote: > > Thanks! So, I assume that as long we make sure we never > explicitly “shutdown” the instance, we are good. Are you also > saying we won’t be able to snapshot a directory with ephemeral > storage and that is why EBS is better? We’re just finding that > to get a reasonable amount of IOPS (gp2) out of EBS at a > reasonable rate, it gets more expensive than an I3. > > > > *From: *Jonathan Haddad <j...@jonhaddad.com > <mailto:j...@jonhaddad.com>> > *Date: *Tuesday, May 23, 2017 at 9:42 AM > *To: *"Gopal, Dhruva" <dhruva.go...@aspect.com> > <mailto:dhruva.go...@aspect.com>, Matija Gobec > <matija0...@gmail.com <mailto:matija0...@gmail.com>>, Bhuvan > Rawal <bhu1ra...@gmail.com <mailto:bhu1ra...@gmail.com>> > *Cc: *"user@cassandra.apache.org > <mailto:user@cassandra.apache.org>" <user@cassandra.apache.org > <mailto:user@cassandra.apache.org>> > > > *Subject: *Re: EC2 instance recommendations > > > > > Oh, so all the data is lost if the instance is shutdown or > restarted (for that instance)? > > > > When you restart the OS, you're technically not shutting down > the instance. As long as the instance isn't stopped / > terminated, your data is fine. I ran my databases on > ephemeral storage for years without issue. In general, > ephemeral storage is going to give you lower latency since > there's no network overhead. EBS is generally cheaper than > ephemeral, is persistent, and you can take snapshots easily. > > > > On Tue, May 23, 2017 at 9:35 AM Gopal, Dhruva > <dhruva.go...@aspect.com <mailto:dhruva.go...@aspect.com>> wrote: > > Oh, so all the data is lost if the instance is shutdown or > restarted (for that instance)? If we take a naïve approach > to backing up the directory, and restoring it, if we ever > have to bring down the instance and back up, will that > work as a strategy? Data is only kept around for 2 days > and is TTL’d after. > > > > *From: *Matija Gobec <matija0...@gmail.com > <mailto:matija0...@gmail.com>> > *Date: *Tuesday, May 23, 2017 at 8:15 AM > *To: *Bhuvan Rawal <bhu1ra...@gmail.com > <mailto:bhu1ra...@gmail.com>> > *Cc: *"Gopal, Dhruva" <dhruva.go...@aspect.com> > <mailto:dhruva.go...@aspect.com>, > "user@cassandra.apache.org > <mailto:user@cassandra.apache.org>" > <user@cassandra.apache.org <mailto:user@cassandra.apache.org>> > *Subject: *Re: EC2 instance recommendations > > > > We are running on I3s since they came out. NVMe SSDs are > really fast and I managed to push them to 75k IOPs. > > As Bhuvan mentioned the i3 storage is ephemeral. If you > can work around it and plan for failure recovery you are > good to go. > > > > I ran Cassandra on m4s before and had no problems with EBS > volumes (gp2) even in low latency use cases. With the cost > of M4 instances and EBS volumes that make sense in IOPs, I > would recommend going with more i3s and working around the > ephemeral issue (if its an issue). > > > > Best, > > Matija > > On Tue, May 23, 2017 at 2:13 AM, Bhuvan Rawal > <bhu1ra...@gmail.com <mailto:bhu1ra...@gmail.com>> wrote: > > i3 instances will undoubtedly give you more meat for > buck - easily 40K+ iops whereas on the other hand EBS > maxes out at 20K PIOPS which is highly expensive (at > times they can cost you significantly more than cost > of instance). > > But they have ephemeral local storage and data is lost > once instance is stopped, you need to be prudent in > case of i series, it is generally used for large > persistent caches. > > > > Regards, > > Bhuvan > > On Tue, May 23, 2017 at 4:55 AM, Gopal, Dhruva > <dhruva.go...@aspect.com > <mailto:dhruva.go...@aspect.com>> wrote: > > Hi – > > We’ve been running M4.2xlarge EC2 instances with > 2-3 TB of storage and have been comparing this to > I-3.2xlarge, which seems more cost effective when > dealing with this amount of storage and from an > IOPS perspective. Does anyone have any > recommendations/ on the I-3s and how it performs > overall, compared to the M4 equivalent? On the > surface, without us having taken it through its > paces performance-wise, it does seem to be pretty > powerful. We just ran through an exercise with a > RAIDed 200 TB volume (as opposed to a non RAIDed 3 > TB volume) and were seeing a 20-30% improvement > with the RAIDed setup, on a 6 node Cassandra ring. > Just looking for any feedback/experience folks may > have had with the I-3s. > > > > Regards, > > *DHRUVA GOPAL* > > *sr. MANAGER, ENGINEERING* > > *REPORTING, ANALYTICS AND BIG DATA* > > *+1 408.325.2011 <tel:+1%20408-325-2011>* *WORK** * > > *+1 408.219.1094 <tel:+1%20408-219-1094>* *MOBILE** * > > *UNITED STATES* > > *dhruva.go...@aspect.com > <mailto:dhruva.go...@aspect.com> * > > *aspect.com <http://www.aspect.com/>* > > *Error! 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