Optane performance as a SLOG

coolrunnings82

Active Member
Mar 26, 2012
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I'm running OmniOS (latest community version + latest Napp-It) baremetal on a Dell R720 with an H310 HBA. It has 128gb of RAM and 6x 8tb Seagate Enterprise 7200rpm drives. These aren't the NAS drives nor the Shingled ones, just straight up capacity SATA. The pool is set up as 3x mirrored vdevs striped together. I am seeing better (or the same) performance with a 400gb Intel S3700 in my real-world iSCSI testing than I am with an Optane 280gb drive. If I turn off sync writes, there's an enormous performance difference. I was under the impression that an Optane SLOG would do a huge amount to minimize the effects of sync... There's gotta be something up here but I've not got the first clue how to troubleshoot it and get an accurate local benchmark for comparison. Some direction on this would be greatly appreciated.
 
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MiniKnight

Well-Known Member
Mar 30, 2012
2,987
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NYC
Can you validate you are running PCIe 3.0 not 2.0 speeds?

Many ZFS dials to turn. Maybe look at @gea 's whitepaper? I'm sure that'll have some setup details on the software side.
 

gea

Well-Known Member
Dec 31, 2010
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DE
I have added this recently so you need 17.06 with a November release date. Goto menu About > Update and download newest 17.06 update.
 

coolrunnings82

Active Member
Mar 26, 2012
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I did that last night and it still wasn't showing up. I'll reboot when I get back to the office and check again. I manually ran many of those benchmarks that were in your guide, @gea and I got MUCH better results with Optane. I'm thinking the problem is related to my 10G networking more than the pool structure at this point. Lovely... Thanks for the help guys!