ISER(4)

📦 version 15.1, in freebsd 14.5, freebsd 15.1, nixpkgs unstable

💅 ISER(4) — the iser girlies' era ✨

okay so this is the iser(4) page from the Kernel Interfaces Manual and honestly bestie, if you're doing block storage over RDMA, this is your main character. let's get into it 🎀

✨ NAME ✨

iser — the iSCSI Extensions for RDMA (iSER) driver 🦋

🌸 SYNOPSIS 🌸

so there's two ways to get this driver doing its thing. take notes 📝

To compile this driver into the kernel, place the following line in the kernel configuration file:

device iser

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

iser_load="YES"

boom. that's it. slay 💅

👑 DESCRIPTION 👑

okay so the iser (iSCSI Extensions for RDMA) initiator driver extends the iSCSI protocol to RDMA. it literally permits data to be transferred directly into and out of SCSI buffers without intermediate data copies — no middleman, no extra steps, we love a direct route 💖

iSER uses the RDMA protocol suite to supply higher bandwidth for block storage transfers (that's the zero copy behavior, iykyk). and to that fact — yes, to that fact — it eliminates the TCP/IP processing overhead while preserving the compatibility with iSCSI protocol. iconic behavior fr fr 🔥

The initiator is the iSCSI/iSER client, which connects to an iSCSI/iSER target, providing local access to a remote block device. The userland component is provided by iscsid(8) and both the kernel and userland are configured using iscsictl(8). two halves, one vibe check 🫶

🧚 SYSCTL VARIABLES 🧚

The following variables are available as both sysctl(8) variables and loader(8) tunables:

  • kern.iser.debug — Verbosity level for log messages from the iser driver. Set to 0 to disable logging or 1 to warn about potential problems. Larger values enable info and debugging output. Defaults to 0. ⭐
lowkey if something's acting sus, this is the knob you turn. 0 = quiet, 1 = "hey bestie, potential problem", bigger = full-on info and debugging tea ☕

🦋 SEE ALSO 🦋

the whole friend group, go read them too 💜

🌈 HISTORY 🌈

The iser subsystem first appeared in FreeBSD 11.0. a true 2016 moment, we stan 🎀

💜 AUTHORS 💜

The iser subsystem was developed by Max Gurtovoy <maxg@mellanox.com> and Sagi Grimberg <sagig@mellanox.com> under sponsorship from Mellanox Technologies. give them their flowers, they ate 👑

and that's the page bestie!! 💖 this one shipped from Debian, dated June 6, 2016 — shoutout to the source and version, and to you for reading all the way to the bottom. periodt. ✨🦋🎀

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