Hi Toke, I don't get SSDs, only spinning drives. And as you mentioned, the impact of VMs is not that much if you use spinning drives. It is more the VM software that matters and thats why we use XEN and not KVM. With some tuning of sysctrl for the VMs it performs good, but bare-metal is still better and should be preferred.
Regards Bernd Am 01.10.2015 um 09:44 schrieb Toke Eskildsen: > Bernd Fehling <bernd.fehl...@uni-bielefeld.de> wrote: >> unfortunately we have to run VMs, otherwise we would waste hardware. >> I thought other solr users are in the same situation but seams that >> other users have tons of hardware available and we are the only one >> having to use VMs. > > We have ~5 smaller (< 1M documents) solr setups that runs under VMWare > (chosen because that is what Operations use for all their virtualization). We > have a single and quite large setup (terabytes of data, billions of > documents) that runs alone on dedicated hardware. Then we have the third > solution: Multiple independent Solr oriented projects that share the same > bare metal. CentOS everywhere BTW. > > We would probably get better hardware utilization by running the hardware > sharing setups in a virtualization system, together with some random other > projects. But I doubt we would gain much for the cost of rocking the > high-performance boat. > > We do have some other bare-metal setups than Solr at our organization (State > and University Library, Denmark), but the default for most other projects is > to use virtualizations. Going mostly bare metal with Solr was an explicit and > performance-driven decision. > > Except for the virtualized instances, we only use local SSDs to hold our > index data. That might affect the trade-off as even slight delays in IO > becomes visible, when storage access times are < 0.1ms instead of > 1ms. I > suspect the relative impact of virtualization is less with spinning drives or > networked storage. > > - Toke Eskildsen >
