On Mar 4, 2016 5:30 PM, "Christian Balzer" <[email protected]> wrote: > > On Fri, 4 Mar 2016 16:09:17 +0900 Shinobu Kinjo wrote: > > > Comparing with these SSDs, > > > > S3710s > > S3610s > > SM863 > > 845DC Pro > > > > which one is more reasonable in terms of performance, cost or whatever? > > S3710s does not sound reasonable to me. > > > Apples and Oranges. > I use S3700s (I would use 3710s only if larger than 200GB, which I have no
This evaluation is interesting to me. > use case for now) exclusively for journals, especially when I can't > control the write usage/patterns. > Their speed and endurance is worth the money in my book. > > I use S3610s for a cache pool, because the price/performance is right, the > endurance is sufficient and the write patterns/volume is well known and > predictable. I am just thinking of this for my next testing cluster. > > > > And I had no luck at all getting the newer versions into a generic > > > kernel or Debian. > > > > So it's not always better to use newer version. Is my understanding > > right? If I don't understand that properly, point it out to me. I'm > > pretty serious about that. > > > The problem was getting their module to compile/integrate as it was > against kernel versions I did not/could not use. This is good to know. > Newer LSI/Avago kernel drivers and firmware are definitely recommended, > given the problems the older stuff has. > Thanks for your suggestion. I will definitely do this. S > Christian > > Cheers, > > Shinobu > > > > > > On Fri, Mar 4, 2016 at 3:17 PM, Christian Balzer <[email protected]> wrote: > > > > > > Hello, > > > > > > On Mon, 29 Feb 2016 15:00:08 -0800 Heath Albritton wrote: > > > > > >> > Did you just do these tests or did you also do the "suitable for > > >> > Ceph" song and dance, as in sync write speed? > > >> > > >> These were done with libaio, so async. I can do a sync test if that > > >> helps. My goal for testing wasn't specifically suitability with ceph, > > >> but overall suitability in my environment, much of which uses async > > >> IO. > > >> > > > Fair enough. > > > Sync tests would be nice, if nothing else to confirm that the Samsung > > > DC level SSDs are suitable and how they compare in that respect to the > > > Intels. > > > > > >> > > >> >> SM863 Pro (default over-provisioning) ~7k IOPS per thread (4 > > >> >> threads, QD32) Intel S3710 ~10k IOPS per thread > > >> >> 845DC Pro ~12k IOPS per thread > > >> >> SM863 (28% over-provisioning) ~18k IOPS per thread > > >> >> > > >> > Very interesting. > > >> > To qualify your values up there, could you provide us with the exact > > >> > models, well size of the SSD will do. > > >> > > >> SM863 was 960GB, I've many of these and the 1.92TB models deployed > > >> 845DC Pro, 800GB > > >> S3710, 800GB > > >> > > > Thanks, pretty much an oranges with oranges comparison then. ^o^ > > > > > >> > Also did you test with a S3700 (I find the 3710s to be a slight > > >> > regression in some ways)? > > >> > And for kicks, did you try over-provisioning with an Intel SSD to > > >> > see the effects there? > > >> > > >> These tests were performed mid-2015. I requested an S3700, but at > > >> that point, I could only get the S3710. I didn't test the Intel with > > >> increased over-provisioning. I suspect it wouldn't have performed > > >> much better as it was already over-provisioned by 28% or thereabouts. > > >> > > > Yeah, my curiosity was mostly if there is similar ratio at work here > > > (might have made more sense for testing purposes to REDUCE the > > > overprovisioning of the Intel) and where the point of diminishing > > > returns is. > > > > > >> It's easy to guess at these sort of things. The total capacity of > > >> flash is in some power of two and the advertised capacity is some > > >> power of ten. Manufacturer's use the difference to buy themselves > > >> some space for garbage collection. So, a terabyte worth of flash is > > >> 1099511627776 bytes. 800GB is 8e+11 bytes with the difference of > > >> about 299GB, which is the space they've set aside for GC. > > >> > > > Ayup, that I was quite aware of. > > > > > >> Again, if there's some tests you'd like to see done, let me know. > > >> It's relatively easy for me to get samples and the tests are a benefit > > >> to me as much as any other. > > >> > > > Well, see above, diminishing returns and all. > > > > > >> > > >> >> I'm seeing the S3710s at ~$1.20/GB and the SM863 around $.63/GB. > > >> >> As such, I'm buying quite a lot of the latter. > > >> > > > >> > I assume those numbers are before over-provisioning the SM863, still > > >> > quite a difference indeed. > > >> > > >> Yes, that's correct. Here's some current pricing: Newegg has the > > >> SM863 960GB at $565 or ~$.59/GB raw. With 28% OP, that yields around > > >> 800GB and around $.71/GB > > >> > > > If I'm reading the (well hidden and only in the PDF) full specs of the > > > 960GB 863 correctly it has an endurance of about 3 DWPD, so the > > > comparable Intel model would be the 3610s. > > > At least when it comes to endurance. > > > Would be interesting to see those two in comparison. ^.^ > > > > > > > > >> >> I've not had them deployed > > >> >> for very long, so I can't attest to anything beyond my synthetic > > >> >> benchmarks. I'm using the LSI 3008 based HBA as well and I've had > > >> >> to use updated firmware and kernel module for it. I haven't > > >> >> checked the kernel that comes with EL7.2, but 7.1 still had > > >> >> problems with the included driver. > > >> >> > > >> > Now THIS is really interesting. > > >> > As you may know several people on this ML including me have issues > > >> > with LSI 3008s and SSDs, including Samsung ones. > > >> > > > >> > Can you provide all the details here, as in: > > >> > IT or IR mode (IT I presume) > > >> > Firmware version > > >> > Kernel driver version > > >> > > >> When initially deployed about a year ago, I had problems with SSDs and > > >> spinning disks. Not sure about any problems specific to Samsung SSDs, > > >> but I've been on the upgrade train. > > >> > > >> I think the stock kernel module is 4.x something or other and LSA, now > > >> Avago has released P9 through P12 in the past year. When I first > > >> started using them, I was on the P9 firmware and kernel module, which > > >> I built from the sources they supply. At this point most of my infra > > >> is on the P10 version. I've not tested the later versions. > > >> > > >> Everything is IT mode where possible. > > >> > > > Yes, at least until kernel 4.1 the module was the 4.0 version. > > > And I had no luck at all getting the newer versions into a generic > > > kernel or Debian. > > > And when I deployed the machines in question P8 was the latest FW from > > > Supermicro. > > > > > > Kernel 4.4 does have the 9.x module, so I guess that's a way forward at > > > least on the kernel side of things (which I think is the more likely > > > culprit). > > > > > > Thanks, > > > > > > Christian > > > -- > > > Christian Balzer Network/Systems Engineer > > > [email protected] Global OnLine Japan/Rakuten Communications > > > http://www.gol.com/ > > > _______________________________________________ > > > ceph-users mailing list > > > [email protected] > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > > > > > -- > Christian Balzer Network/Systems Engineer > [email protected] Global OnLine Japan/Rakuten Communications > http://www.gol.com/
_______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
