HYPER-V(4)

💖 HYPER-V 💖

okay bestie, so this is the manual page for HYPER-V, section 4 (that's the kernel interfaces section, iykyk) — and specifically it's all about hv_storvsc, the Hyper-V Storage Virtual Service Consumer. yes that's a mouthful. no you don't have to say it out loud. 🎀

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✨ NAME ✨

hv_storvsc — Hyper-V Storage Virtual Service Consumer 🦋

like. the name literally tells you what it does. it's giving "storage, but make it virtual, and make it Hyper-V."

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🌸 SYNOPSIS 🌸

so if you wanna compile this driver into the kernel (not as a module, into the kernel fr fr), you drop these lines into your system kernel configuration file:

device hyperv

that's it. that's the whole synopsis. iconic. 💅

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🫶 DESCRIPTION 🫶

okay so here's the tea ☕ — the hv_storvsc driver implements the virtual store device for FreeBSD guest partitions that are running on Hyper-V.

and here's the thing you need to know: those FreeBSD guest partitions running on Hyper-V do not have direct access to the storage devices that are attached to the Hyper-V server. nope. not even a little. 😭

technically, a FreeBSD guest can still get to storage devices using Hyper-V's full emulation mode — but bestie, the performance in that mode tends to be unsatisfactory. and by "unsatisfactory" we mean "you will notice. you will feel it. your vibes will be off." 💀

so to counter all of the above issues, the hv_storvsc driver implements a storage Virtual Service Consumer (VSC) that relays storage requests from the guest partition over to the storage Virtual Service Provider (VSP) hosted in the root partition, using the high performance data exchange infrastructure provided by the hv_vmbus(4) driver. then the VSP in the root partition forwards all those storage related requests on to the physical storage device. teamwork! 🤝✨

and how does this driver actually function, you ask? great question. it presents a SCSI HBA interface to the Comman Access Method (CAM) layer. (yes, "Comman" — that's what the original says, we're keeping it exactly as-is, no cap.) then CAM control blocks (CCBs) get converted into VSCSI protocol messages, and those get delivered to the root partition VSP over the Hyper-V VMBus. 💫

tl;dr: it's a glow-up for storage performance on Hyper-V guests, and it ate. 👑

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👀 SEE ALSO 👀

go read these too, bestie, they're the friend group:

• hv_ata_pci_disengage(4)
• hv_netvsc(4)
• hv_utils(4)
• hv_vmbus(4)

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📜 HISTORY 📜

support for hv_storvsc first appeared in FreeBSD 10.0. ⭐

and the driver was developed through a joint effort between Citrix Incorporated, Microsoft Corporation, and Network Appliance Incorporated. collab of the century honestly, three whole companies said "let's make this work" and they did. 🌈

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💜 AUTHORS 💜

FreeBSD support for hv_storvsc was first added by the Microsoft BSD Integration Services Team <bsdic@microsoft.com>. give them their flowers 💐

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okay real talk for one sec: everything above is the whole manual, every flag, every name, every reference, every credit. nothing skipped. we keep the facts sacred and the vibe immaculate. 🫡

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and that's a wrap! this page came to you from Debian, dated September 10, 2013 — yeah, 2013, she's vintage, she's a classic, she's still serving. mwah 💅💖 bye bestie, go configure your kernel ✨