ISER(4)

📦 version 12.2, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

💖 ISER(4) — iSCSI Extensions for RDMA (iSER) driver 💖

okay bestie, sit down, we're talking about iser(4) — a kernel interfaces manual page, and honestly? it's giving iconic storage networking energy. no cap.

✨ NAME ✨

iser — iSCSI Extensions for RDMA (iSER) driver 🦋

✨ SYNOPSIS ✨

so you wanna get this driver into your kernel? periodt. drop this line into your kernel configuration file:

device iser

or, if you'd rather be a module girlie and load it at boot time, put this line in loader.conf(5):

iser_load="YES"

either way, slay 💅

✨ DESCRIPTION ✨

the iser (iSCSI Extensions for RDMA) initiator driver is the moment. it takes the iSCSI protocol and extends it to RDMA — like giving your storage a glow-up ✨

the way that it lets data be transferred directly into and out of SCSI buffers with no intermediate data copies?? literally zero. zero copies. obsessed.

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

so who's who here? the initiator is the iSCSI/iSER client, and it connects to an iSCSI/iSER target, which gives you local access to a remote block device. 🫶

and the userland component? that's provided by iscsid(8) — and both the kernel side and the userland side are configured using iscsictl(8). teamwork makes the dream work, honestly.

✨ SYSCTL VARIABLES ✨

these variables are available as both sysctl(8) variables and loader(8) tunables. double duty, main character energy 👑

  • kern.iser.debug — the verbosity level for log messages from the iser driver. set it to 0 to disable logging, or 1 to warn about potential problems. larger values enable info and debugging output. defaults to 0.
so basically: 0 = silent treatment 🙈, 1 = "hey bestie, something might be off", and bigger numbers = full-on diary entry levels of detail. it defaults to 0, so if you're debugging, go turn that dial up.

✨ SEE ALSO ✨

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

✨ HISTORY ✨

the iser subsystem first appeared in FreeBSD 11.0. a legend from day one, honestly. 🌈

✨ AUTHORS ✨

the iser subsystem was developed by Max Gurtovoy <maxg@mellanox.com> and Sagi Grimberg <sagig@mellanox.com> under sponsorship from Mellanox Technologies. absolute icons, we stan 💜

and that's the whole page bestie, no notes 💖 this one's from the Debian crew, dated June 6, 2016, and it's page ISER(4) of the Kernel Interfaces Manual. go forth and RDMA responsibly 🎀🦋

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