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 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. > > 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. Newer LSI/Avago kernel drivers and firmware are definitely recommended, given the problems the older stuff has. Christian > Cheers, > Shinobu > > > On Fri, Mar 4, 2016 at 3:17 PM, Christian Balzer <chibi@xxxxxxx> 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 > > chibi@xxxxxxx Global OnLine Japan/Rakuten Communications > > http://www.gol.com/ > > _______________________________________________ > > ceph-users mailing list > > ceph-users@xxxxxxxxxxxxxx > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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