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How do I know when a SATA AHCI controller supports hotplugging (for servers running Linux)? Apparently, whether AHCI is enabled or not doesn't mean everything. Can I query the driver in /sys for support for this?

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If AHCI is turned on and hotplugging doesn't work, your controller is defective. – Michael Hampton Oct 15 '13 at 7:23
So hotplugging is always a part of the AHCI spec? – Halfgaar Oct 15 '13 at 7:37
Yes. As far as I know, it only didn't work properly on some old NVIDIA chipsets on really low end desktop motherboards several years ago. It should work on anything current. – Michael Hampton Oct 15 '13 at 7:42
Yet, when I asked a dedicated server provider if their mdadm software RAID machines supported AHCI and hotplugging, they said that AHCI was supported, but hotplugging wasn't. Do they just now know what they're talking about? – Halfgaar Oct 15 '13 at 7:52
It's quite possible that they have no clue. :) Or they could be using very low-end hardware, which is unfortunately all too common. – Michael Hampton Oct 15 '13 at 7:54

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