> 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. >> 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 > 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. 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. 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. >> 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 >> 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. _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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