Hi Garrett, Thank you for your response!
> Devices with PLP and DRAM may out perform those without DRAM. And honestly > this meant to be a write only workload so hitting ram on the drive is going > to be tons faster for latency sensitive ops. So for my money that’s where I’d > go. (Yes this slightly redundant to ram in ARC but ARC has no knowledge of > power protection so it has to go all the way to disk to be sure. So PLP will > be a performance win.) You wrote “ARC”, but did you mean “ZIL”? - for the writes, the ZIL (not ARC) is used, right? Mapping to SSD use, it’s Slog vs. L2ARC? For Slog, PLP is needed, but not so for L2ARC, correct? Rethinking things, maybe the “hot” data should really just be an L2ARC (rather than an SSD-based zpool). Does the L2ARC on Illumos survive reboots? If so, than perhaps a rather large (~4TB) of L2ARC (using SSDs) would effectively cover all fast-read needs, with a rather small (100MB?) Slog (using SSDs with PLP) covering all fast-write needs. Then the zpool itself could be slow and very safe (e.g., a raidz3 of 5200 RPM HDDs, even SMR/shingled would be okay, I imagine). Thoughts? Thanks again, Kent ------------------------------------------ illumos: illumos-discuss Permalink: https://illumos.topicbox.com/groups/discuss/T1d25146fb4ce0f44-M22152ff0369a3ac897439f43 Delivery options: https://illumos.topicbox.com/groups/discuss/subscription
