Yeah, I would only start a previous-generation instance for non-production purposes at this point and I suspect that many of them will be retired sooner or later.
Given a choice, I'd use i2 instances for most purposes, and use the d2 instances where storage volume and access patterns demanded it. I have seen reports of other instances running SSD-backed EBS. Not sure if the network lag is a significant issue in that case or not, but it would open up other options for Cassandra clusters. On Mon, Feb 1, 2016 at 1:55 PM, Jack Krupansky <jack.krupan...@gmail.com> wrote: > Thanks. My typo - I referenced "C2 Dense Storage" which is really "D2 > Dense Storage". > > The remaining question is whether any of the "Previous Generation > Instances" should be publicly recommended going forward. > > And whether non-SSD instances should be recommended going forward as well. > sure, technically, someone could use the legacy instances, but the question > is what we should be recommending as best practice going forward. > > Yeah, the i2 instances look like the sweet spot for any non-EBS clusters. > > -- Jack Krupansky > > On Mon, Feb 1, 2016 at 4:30 PM, Steve Robenalt <sroben...@highwire.org> > wrote: > >> Hi Jack, >> >> At the bottom of the instance-types page, there is a link to the previous >> generations, which includes the older series (m1, m2, etc), many of which >> have HDD options. >> >> There are also the d2 (Dense Storage) instances in the current generation >> that include various combos of local HDDs. >> >> The i2 series has good sized SSDs available, and has the advanced >> networking option, which is also useful for Cassandra. The enhanced >> networking is available with other instance types as well, as you'll see on >> the feature list under each type. >> >> Steve >> >> >> >> On Mon, Feb 1, 2016 at 1:17 PM, Jack Krupansky <jack.krupan...@gmail.com> >> wrote: >> >>> Thanks. Reading a little bit on AWS, and back to my SSD vs. magnetic >>> question, it seems like magnetic (HDD) is no longer a recommended storage >>> option for databases on AWS. In particular, only the C2 Dense Storage >>> instances have local magnetic storage - all the other instance types are >>> SSD or EBS-only - and EBS Magnetic is only recommended for "Infrequent Data >>> Access." >>> >>> For the record, that AWS doc has Cassandra listed as a use case for i2 >>> instance types. >>> >>> Also, the AWS doc lists EBS io2 for the NoSQL database use case and gp2 >>> only for the "small to medium databases" use case. >>> >>> Do older instances with local HDD still exist on AWS (m1, m2, etc.)? Is >>> the doc simply for any newly started instances? >>> >>> See: >>> https://aws.amazon.com/ec2/instance-types/ >>> http://aws.amazon.com/ebs/details/ >>> >>> >>> -- Jack Krupansky >>> >>> On Mon, Feb 1, 2016 at 2:09 PM, Jeff Jirsa <jeff.ji...@crowdstrike.com> >>> wrote: >>> >>>> > My apologies if my questions are actually answered on the video or >>>> slides, I just did a quick scan of the slide text. >>>> >>>> Virtually all of them are covered. >>>> >>>> > I'm curious where the EBS physical devices actually reside - are they >>>> in the same rack, the same data center, same availability zone? I mean, >>>> people try to minimize network latency between nodes, so how exactly is EBS >>>> able to avoid network latency? >>>> >>>> Not published,and probably not a straight forward answer (probably have >>>> redundancy cross-az, if it matches some of their other published >>>> behaviors). The promise they give you is ‘iops’, with a certain block size. >>>> Some instance types are optimized for dedicated, ebs-only network >>>> interfaces. Like most things in cassandra / cloud, the only way to know for >>>> sure is to test it yourself and see if observed latency is acceptable (or >>>> trust our testing, if you assume we’re sufficiently smart and honest). >>>> >>>> > Did your test use Amazon EBS–Optimized Instances? >>>> >>>> We tested dozens of instance type/size combinations (literally). The >>>> best performance was clearly with ebs-optimized instances that also have >>>> enhanced networking (c4, m4, etc) - slide 43 >>>> >>>> > SSD or magnetic or does it make any difference? >>>> >>>> SSD, GP2 (slide 64) >>>> >>>> > What info is available on EBS performance at peak times, when >>>> multiple AWS customers have spikes of demand? >>>> >>>> Not published, but experiments show that we can hit 10k iops all day >>>> every day with only trivial noisy neighbor problems, not enough to impact a >>>> real cluster (slide 58) >>>> >>>> > Is RAID much of a factor or help at all using EBS? >>>> >>>> You can use RAID to get higher IOPS than you’d normally get by default >>>> (GP2 IOPS cap is 10k, which you get with a 3.333T volume – if you need more >>>> than 10k, you can stripe volumes together up to the ebs network link max) >>>> (hinted at in slide 64) >>>> >>>> > How exactly is EBS provisioned in terms of its own HA - I mean, with >>>> a properly configured Cassandra cluster RF provides HA, so what is the >>>> equivalent for EBS? If I have RF=3, what assurance is there that those >>>> three EBS volumes aren't all in the same physical rack? >>>> >>>> There is HA, I’m not sure that AWS publishes specifics. Occasionally >>>> specific volumes will have issues (hypervisor’s dedicated ethernet link to >>>> EBS network fails, for example). Occasionally instances will have issues. >>>> The volume-specific issues seem to be less common than the instance-store >>>> “instance retired” or “instance is running on degraded hardware” events. >>>> Stop/Start and you’ve recovered (possible with EBS, not possible with >>>> instance store). The assurances are in AWS’ SLA – if the SLA is >>>> insufficient (and it probably is insufficient), use more than one AZ and/or >>>> AWS region or cloud vendor. >>>> >>>> > For multi-data center operation, what configuration options assure >>>> that the EBS volumes for each DC are truly physically separated? >>>> >>>> It used to be true that EBS control plane for a given region spanned >>>> AZs. That’s no longer true. AWS asserts that failure modes for each AZ are >>>> isolated (data may replicate between AZs, but a full outage in us-east-1a >>>> shouldn’t affect running ebs volumes in us-east-1b or us-east-1c). Slide 65 >>>> >>>> > In terms of syncing data for the commit log, if the OS call to sync >>>> an EBS volume returns, is the commit log data absolutely 100% synced at the >>>> hardware level on the EBS end, such that a power failure of the systems on >>>> which the EBS volumes reside will still guarantee availability of the >>>> fsynced data. As well, is return from fsync an absolute guarantee of >>>> sstable durability when Cassandra is about to delete the commit log, >>>> including when the two are on different volumes? In practice, we would like >>>> some significant degree of pipelining of data, such as during the full >>>> processing of flushing memtables, but for the fsync at the end a solid >>>> guarantee is needed. >>>> >>>> Most of the answers in this block are “probably not 100%, you should be >>>> writing to more than one host/AZ/DC/vendor to protect your organization >>>> from failures”. AWS targets something like 0.1% annual failure rate per >>>> volume and 99.999% availability (slide 66). We believe they’re exceeding >>>> those goals (at least based with the petabytes of data we have on gp2 >>>> volumes). >>>> >>>> >>>> >>>> From: Jack Krupansky >>>> Reply-To: "user@cassandra.apache.org" >>>> Date: Monday, February 1, 2016 at 5:51 AM >>>> >>>> To: "user@cassandra.apache.org" >>>> Subject: Re: EC2 storage options for C* >>>> >>>> I'm not a fan of guy - this appears to be the slideshare corresponding >>>> to the video: >>>> >>>> http://www.slideshare.net/AmazonWebServices/bdt323-amazon-ebs-cassandra-1-million-writes-per-second >>>> >>>> My apologies if my questions are actually answered on the video or >>>> slides, I just did a quick scan of the slide text. >>>> >>>> I'm curious where the EBS physical devices actually reside - are they >>>> in the same rack, the same data center, same availability zone? I mean, >>>> people try to minimize network latency between nodes, so how exactly is EBS >>>> able to avoid network latency? >>>> >>>> Did your test use Amazon EBS–Optimized Instances? >>>> >>>> SSD or magnetic or does it make any difference? >>>> >>>> What info is available on EBS performance at peak times, when multiple >>>> AWS customers have spikes of demand? >>>> >>>> Is RAID much of a factor or help at all using EBS? >>>> >>>> How exactly is EBS provisioned in terms of its own HA - I mean, with a >>>> properly configured Cassandra cluster RF provides HA, so what is the >>>> equivalent for EBS? If I have RF=3, what assurance is there that those >>>> three EBS volumes aren't all in the same physical rack? >>>> >>>> For multi-data center operation, what configuration options assure that >>>> the EBS volumes for each DC are truly physically separated? >>>> >>>> In terms of syncing data for the commit log, if the OS call to sync an >>>> EBS volume returns, is the commit log data absolutely 100% synced at the >>>> hardware level on the EBS end, such that a power failure of the systems on >>>> which the EBS volumes reside will still guarantee availability of the >>>> fsynced data. As well, is return from fsync an absolute guarantee of >>>> sstable durability when Cassandra is about to delete the commit log, >>>> including when the two are on different volumes? In practice, we would like >>>> some significant degree of pipelining of data, such as during the full >>>> processing of flushing memtables, but for the fsync at the end a solid >>>> guarantee is needed. >>>> >>>> >>>> -- Jack Krupansky >>>> >>>> On Mon, Feb 1, 2016 at 12:56 AM, Eric Plowe <eric.pl...@gmail.com> >>>> wrote: >>>> >>>>> Jeff, >>>>> >>>>> If EBS goes down, then EBS Gp2 will go down as well, no? I'm not >>>>> discounting EBS, but prior outages are worrisome. >>>>> >>>>> >>>>> On Sunday, January 31, 2016, Jeff Jirsa <jeff.ji...@crowdstrike.com> >>>>> wrote: >>>>> >>>>>> Free to choose what you'd like, but EBS outages were also addressed >>>>>> in that video (second half, discussion by Dennis Opacki). 2016 EBS isn't >>>>>> the same as 2011 EBS. >>>>>> >>>>>> -- >>>>>> Jeff Jirsa >>>>>> >>>>>> >>>>>> On Jan 31, 2016, at 8:27 PM, Eric Plowe <eric.pl...@gmail.com> wrote: >>>>>> >>>>>> Thank you all for the suggestions. I'm torn between GP2 vs Ephemeral. >>>>>> GP2 after testing is a viable contender for our workload. The only worry >>>>>> I >>>>>> have is EBS outages, which have happened. >>>>>> >>>>>> On Sunday, January 31, 2016, Jeff Jirsa <jeff.ji...@crowdstrike.com> >>>>>> wrote: >>>>>> >>>>>>> Also in that video - it's long but worth watching >>>>>>> >>>>>>> We tested up to 1M reads/second as well, blowing out page cache to >>>>>>> ensure we weren't "just" reading from memory >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> Jeff Jirsa >>>>>>> >>>>>>> >>>>>>> On Jan 31, 2016, at 9:52 AM, Jack Krupansky < >>>>>>> jack.krupan...@gmail.com> wrote: >>>>>>> >>>>>>> How about reads? Any differences between read-intensive and >>>>>>> write-intensive workloads? >>>>>>> >>>>>>> -- Jack Krupansky >>>>>>> >>>>>>> On Sun, Jan 31, 2016 at 3:13 AM, Jeff Jirsa < >>>>>>> jeff.ji...@crowdstrike.com> wrote: >>>>>>> >>>>>>>> Hi John, >>>>>>>> >>>>>>>> We run using 4T GP2 volumes, which guarantee 10k iops. Even at 1M >>>>>>>> writes per second on 60 nodes, we didn’t come close to hitting even 50% >>>>>>>> utilization (10k is more than enough for most workloads). PIOPS is not >>>>>>>> necessary. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> From: John Wong >>>>>>>> Reply-To: "user@cassandra.apache.org" >>>>>>>> Date: Saturday, January 30, 2016 at 3:07 PM >>>>>>>> To: "user@cassandra.apache.org" >>>>>>>> Subject: Re: EC2 storage options for C* >>>>>>>> >>>>>>>> For production I'd stick with ephemeral disks (aka instance >>>>>>>> storage) if you have running a lot of transaction. >>>>>>>> However, for regular small testing/qa cluster, or something you >>>>>>>> know you want to reload often, EBS is definitely good enough and we >>>>>>>> haven't >>>>>>>> had issues 99%. The 1% is kind of anomaly where we have flush blocked. >>>>>>>> >>>>>>>> But Jeff, kudo that you are able to use EBS. I didn't go through >>>>>>>> the video, do you actually use PIOPS or just standard GP2 in your >>>>>>>> production cluster? >>>>>>>> >>>>>>>> On Sat, Jan 30, 2016 at 1:28 PM, Bryan Cheng <br...@blockcypher.com >>>>>>>> > wrote: >>>>>>>> >>>>>>>>> Yep, that motivated my question "Do you have any idea what kind >>>>>>>>> of disk performance you need?". If you need the performance, its hard >>>>>>>>> to >>>>>>>>> beat ephemeral SSD in RAID 0 on EC2, and its a solid, battle tested >>>>>>>>> configuration. If you don't, though, EBS GP2 will save a _lot_ of >>>>>>>>> headache. >>>>>>>>> >>>>>>>>> Personally, on small clusters like ours (12 nodes), we've found >>>>>>>>> our choice of instance dictated much more by the balance of price, >>>>>>>>> CPU, and >>>>>>>>> memory. We're using GP2 SSD and we find that for our patterns the >>>>>>>>> disk is >>>>>>>>> rarely the bottleneck. YMMV, of course. >>>>>>>>> >>>>>>>>> On Fri, Jan 29, 2016 at 7:32 PM, Jeff Jirsa < >>>>>>>>> jeff.ji...@crowdstrike.com> wrote: >>>>>>>>> >>>>>>>>>> If you have to ask that question, I strongly recommend m4 or c4 >>>>>>>>>> instances with GP2 EBS. When you don’t care about replacing a node >>>>>>>>>> because >>>>>>>>>> of an instance failure, go with i2+ephemerals. Until then, GP2 EBS is >>>>>>>>>> capable of amazing things, and greatly simplifies life. >>>>>>>>>> >>>>>>>>>> We gave a talk on this topic at both Cassandra Summit and AWS >>>>>>>>>> re:Invent: https://www.youtube.com/watch?v=1R-mgOcOSd4 It’s very >>>>>>>>>> much a viable option, despite any old documents online that say >>>>>>>>>> otherwise. >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> From: Eric Plowe >>>>>>>>>> Reply-To: "user@cassandra.apache.org" >>>>>>>>>> Date: Friday, January 29, 2016 at 4:33 PM >>>>>>>>>> To: "user@cassandra.apache.org" >>>>>>>>>> Subject: EC2 storage options for C* >>>>>>>>>> >>>>>>>>>> My company is planning on rolling out a C* cluster in EC2. We are >>>>>>>>>> thinking about going with ephemeral SSDs. The question is this: >>>>>>>>>> Should we >>>>>>>>>> put two in RAID 0 or just go with one? We currently run a cluster in >>>>>>>>>> our >>>>>>>>>> data center with 2 250gig Samsung 850 EVO's in RAID 0 and we are >>>>>>>>>> happy with >>>>>>>>>> the performance we are seeing thus far. >>>>>>>>>> >>>>>>>>>> Thanks! >>>>>>>>>> >>>>>>>>>> Eric >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>> >>> >> >> >> -- >> Steve Robenalt >> Software Architect >> sroben...@highwire.org <bza...@highwire.org> >> (office/cell): 916-505-1785 >> >> HighWire Press, Inc. >> 425 Broadway St, Redwood City, CA 94063 >> www.highwire.org >> >> Technology for Scholarly Communication >> > > -- Steve Robenalt Software Architect sroben...@highwire.org <bza...@highwire.org> (office/cell): 916-505-1785 HighWire Press, Inc. 425 Broadway St, Redwood City, CA 94063 www.highwire.org Technology for Scholarly Communication
