03 November 2018

3rd of November

Farm status
Intel GPUs
All off

Nvidia GPUs
All off

Raspberry Pis
12 crunching Einstein BRP4 work

File server
I’ve converted it over to Linux and that is when the problems started. The RAID controller wasn’t recognised, even in JBOD mode so I removed it and plugged the drives directly into the motherboard SATA ports. I setup ZFS on the 4 drives without any issues. When I copied the files back it took ages and was indicating it was only doing 75MB/sec write speed which I think is pretty slow. Maybe the ZFS overheads are such that is a good figure.

I managed to get the RAID controller going but write speeds are still 75MB/sec. I have ordered a PCIe to NVMe adapter and a NVMe SSD to use as a cache and logging drive. NVMe SSD’s are somewhat faster than SATA which only go up to 6 gigabit/sec. Hopefully this will speed things up. I'm not sure if I need a second one (ie one for cache and another for logging).

Networking updated
I ordered and received a couple of 10Gbit network switches (the ones with 2 x 10Gbe and 8 x 1Gbe) and put them in. I also got a full 8 x 10Gbe switch to plug into the router so that I can get to use this higher speed down to the smaller switches and into the file server. I still have an extra 10Gbe network card that I could put into the file server.

New LIGO search
Einstein have a new search they are conducting on the LIGO O1 data. Its CPU only. I did some testing to see how it performs on the Intel GPU machines using all available threads versus using half of them. It certainly does more work using all threads.

I started doing the same on the AMD machines but after the first batch running on half the threads there isn't any new work available. Being 1st generation Ryzen’s they are pretty poor on the hyperthreading front, whereas Intel have had quite a few generations to optimise their designs.

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