SYSID(5)

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version 1.8.16.1 · 10 versions
, in ubuntu stonking

💖 SYSID(5) 💖

ok so bestie, this is a page from the AFS File Reference and it's all about sysid — the little file that keeps track of your file server machine's interface addresses. it's giving "quiet file, big job" honestly. let's get into it 🫶

✨ NAME ✨

sysid — literally just a file that lists the file server machine interface addresses registered in the VLDB 📋

🌸 DESCRIPTION 🌸

okay so picture this: the sysid file is the place where the network interface addresses get recorded — specifically the ones that the File Server (that's the fileserver process, hey bestie 👋) registers in the Volume Location Database, aka the VLDB.

every single time the File Server restarts, it does this whole little routine, no cap:

  1. it builds a list of interfaces on the local machine by reading the /var/lib/openafs/local/NetInfo file — but only if that file exists 💅
  2. if /var/lib/openafs/local/NetInfo doesn't exist, it just uses the list of network interfaces that are configured with the operating system instead
  3. then it removes from that list any addresses that show up in the /var/lib/openafs/local/NetRestrict file — again, only if that file exists
  4. it takes the resulting list, writes it into the sysid file in binary format, and registers those interfaces in the VLDB ✨

so why do we care?? because when the Cache Manager asks for volume location information, the Volume Location (VL) Server hands over all of the interfaces registered for every server machine that houses the volume. and that's iconic, actually, because it means the Cache Manager can use multiple addresses when it's accessing AFS data stored on a multihomed file server machine 🔥 multiple addresses = main character energy.

🚨 CAUTIONS 🚨

bestie. listen. this part is serious. 🙈

the sysid file is unique to each file server machine and it must not be copied from one machine to another. do not do it. not even once.

and if your cell has a habit of copying the contents of the /var/lib/openafs/local directory from an existing file server machine onto a newly installed one?? 💀 first of all, bold. second of all, be sure to remove the sysid file from the new machine before you start the "fs" trio of processes — and yes, that trio includes the fileserver process.

also important: a maximum of 15 file server interface addresses can be registered in the VLDB. that's the ceiling. that's the limit. no more than that, fr fr.

👀 SEE ALSO 👀

go read those next, you're doing amazing sweetie ✨

IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.

This documentation is covered by the IBM Public License Version 1.0. It was converted from HTML to POD by software written by Chas Williams and Russ Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.

and that's the whole page bestie!! 🎀 this one's from OpenAFS, dated 2026-07-27 — mwah, periodt 💅💖

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