ZFS people.
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ZFS people. Is it worth having a dedicated special? On a 9 disk SSD array?
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/dev/rdsk/c5t1d0s2replied to :PUA: Shlee fucked around and last edited by
@shlee (dedicated spare?)
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/dev/rdsk/c5t1d0s2replied to :PUA: Shlee fucked around and last edited by
@shlee ah right. Never used it, but unless you’re doing a LOT of metadata work it’s probably not worth the hassle of setting it up
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:PUA: Shlee fucked around andreplied to /dev/rdsk/c5t1d0s2 last edited by
@jpm feels like it. Wonder what the threshold is tho.
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ss23replied to :PUA: Shlee fucked around and last edited by
@shlee If you've already got SSDs for the array, then I don't think it'd be super useful? That being said, mine is HDDs and only Optane for SLOG, so I'm not in a comparable situation...
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noodlereplied to :PUA: Shlee fucked around and last edited by [email protected]
@shlee It depends. On an SSD array probably not. It reduces redundancy too (for the same number of drives), because it is a vital part of the pool (unlike, say, a metadata only L2ARC).
For longevity consider doing things to reduce write amplification, like enabling compression* and, if you need to do a lot of small sync writes, having a SLOG.
*As of whenever I last read things, compression also makes block managent 'smarter'.
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/dev/rdsk/c5t1d0s2replied to :PUA: Shlee fucked around and last edited by
@shlee my feel would be if you’ve got either extremely large dedup datasets, or lots of very large source code repositories (or you’ve disabled the RAM cache entirely)
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:PUA: Shlee fucked around andreplied to ss23 last edited by [email protected]
@ss23 thanks. I’ll have a 280GB ZIL so I was thinking I could partition it for special and ZIL as a mirror on the two optanes.
It is a waste to have 280GB for the ZIL but they exist as a “you have one job” kind of deal and the special drive might just be over engineering it.
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ss23replied to :PUA: Shlee fucked around and last edited by
@shlee Hmm, if you have latency sensitive sync writes, could that kind of set up hurt it, if the device ends up getting a write queue that includes the ZIL writes, but only after it finishes the special writes? I haven't looked at the relevant parts of the code though, so just at a guess. Guessing some more, this sounds like it'd go in the "more complicated for little benefit" box for me. But if you do it, let us know! I didn't even think of using my Optane like that!
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:PUA: Shlee fucked around andreplied to ss23 last edited by
@ss23 I might need to actually study this… but I feel like I should step away from the fancy vdev.