I'm experimenting with bcache to see about using the ephemeral storage as a cache backed with EBS. Not sure if that makes sense in your use case though.
On Tue, May 23, 2017 at 9:43 AM Jonathan Haddad <j...@jonhaddad.com> wrote: > > 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> > 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> >> *Date: *Tuesday, May 23, 2017 at 8:15 AM >> *To: *Bhuvan Rawal <bhu1ra...@gmail.com> >> *Cc: *"Gopal, Dhruva" <dhruva.go...@aspect.com>, " >> user@cassandra.apache.org" <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> >> 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> >> 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 <+1%20408-325-2011>* *WORK* >> >> *+1 408.219.1094 <+1%20408-219-1094>* *MOBILE* >> >> *UNITED STATES* >> >> *dhruva.go...@aspect.com <dhruva.go...@aspect.com> * >> >> *aspect.com <http://www.aspect.com/>* >> >> [image: scription: http://webapp2.aspect.com/EmailSigLogo-rev.jpg] >> >> >> >> This email (including any attachments) is proprietary to Aspect Software, >> Inc. and may contain information that is confidential. If you have received >> this message in error, please do not read, copy or forward this message. >> Please notify the sender immediately, delete it from your system and >> destroy any copies. You may not further disclose or distribute this email >> or its attachments. >> >> This email (including any attachments) is proprietary to Aspect Software, >> Inc. and may contain information that is confidential. If you have received >> this message in error, please do not read, copy or forward this message. >> Please notify the sender immediately, delete it from your system and >> destroy any copies. You may not further disclose or distribute this email >> or its attachments. >> >
