A couple weeks ago I upgraded one my home lab machines I use for benchmarking. Aside from getting a new Ryzen, the main change was getting a bunch of Samsung 990 PRO M.2 SSDs for storage. And the performance I'm seeing is rather atrocious :-(
For most workloads (reads/writes, sequential/random) it works fine, e.g. for random writes I can get ~50k IOPS (iodepth=1) quite easily. But as soon as I ask fio to do fsyncs (fsync=1), the performance just absolutely tanks to ~200 IOPS.
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@tomasv At this point I don't really have a better explanation other than Samsung intentionally slowing down client SSDs to maintain market segmentation. Every generation of Samsung client NVMe is getting slower fsync. And FUA writes are even slower than writes followed by a full-cache-flush.
I've basically given up on using them.
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@tomasv Just look at the numbers here: https://gist.github.com/anarazel/b527e5317bb7d58483a9858f5f2435ca
Samsung is just atrociously bad.
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@AndresFreundTec Yeah, seems like that. Any suggestion what other devices to use for a home lab machine?
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@tomasv I wish I had a good default answer. [Nearly] all the stupid SSD benchmarking sites are not testing durable write performance.
I have a few WD NVMes that I am reasonably happy with - they do heat up a fair bit under load though. I have a few Sabrents that are OK. I have an ADATA, which I am fairly certain is lying about cache flushes, so I'd hesitate.
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