libnvme(2)

💖 NAME 💖

enum nvme_id_ctrl_vwc — the volatile write cache, bestie. Yes we're talking about the controller's little cache situation ✨

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🌸 SYNOPSIS 🌸

enum nvme_id_ctrl_vwc {
    NVME_CTRL_VWC_PRESENT ,
    NVME_CTRL_VWC_FLUSH

};

okay so it's literally just two constants, no drama, and yet they're lowkey important 👑

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🎀 Constants 🎀

• NVME_CTRL_VWC_PRESENT — if this bit is set, it means a volatile write cache is present on this controller, periodt. And here's the tea: if there IS a volatile write cache, then the host is the one who decides whether it's enabled, by sending a Set Features command with the value NVME_FEAT_FID_VOLATILE_WC. So the host has main character energy here, not the drive 🫶
• NVME_CTRL_VWC_FLUSH — this one's a mask, and its whole job is to pull out the value that tells you the flush command behavior 💅

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ngl bestie, that's the whole enum. Two constants, zero plot twists, and yet your storage stack will absolutely notice if you get them wrong 😭

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and that's a wrap on the enum nvme_id_ctrl_vwc page from the libnvme API Manual (section 2), page date July 2026 🦋 slay, go forth and read those controller bits, iykyk 💜