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OpenAFS Status

OpenAFS Status. new year, new challenges Derrick Brashear The OpenAFS Project 3 June 2009. First things first. If we’re going to have a live debug session, we need to know what to debug. Because after all, OpenAFS is bug-free, right?. This all sounds familiar.

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OpenAFS Status

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  1. OpenAFS Status • new year, new challenges • Derrick Brashear • The OpenAFS Project • 3 June 2009

  2. First things first • If we’re going to have a live debug session, we need to know what to debug. • Because after all, OpenAFS is bug-free, right?

  3. This all sounds familiar • New stable release coming. (1.4.11) • New development releases continue apace. (1.5.60, 1.5.61 soon)

  4. Recently resolved issues • A race in the namei fileserver’s background sync support, ih_sync_all. • Could cause volumes to go offline during a release until salvage. • Linux post-2.6.29 keyring-to-group PAG copying Oops issue. • Fileserver host tracking/hashing (again). • Most Linux mmap-close-write corruption cases fixed.(*) • Linux byte range (client-only) locking now works!

  5. In the past year • OpenAFS 1.4.8 shipped with a large number of fixes to Rx packet tracking. • Double-frees • Races

  6. New in 1.4.10 • Security fixes (sigh) • Rx in-use packet freeing fix. • Fix for Rx idleness tracking. • Corrections for ubik database recovery process.

  7. New in 1.4.10 • Multiple (more than 2) local realms. • Requires username space to be the same. (“shadow” in any realm is the same person) • List realms one per line in /usr/afs/etc/krb.conf or equivalent.

  8. 1.4.10 open issues • Panic in Linux VFS layer (infrequent). • Page mapping with close followed by write on Linux can lose data where file >> cache. • Fileserver host list can be corrupted.

  9. New in 1.5.60 • A fix for the ih_sync_all bug. • Hartmut pointed us the right way here. • Retry in the event of volserver transaction creation. • Based on Rainer Toebbicke’s patch. • Dragonfly BSD userland support. • Contributed by Matt Benjamin. • Cache type abstraction. • Thanks to Marc Dionne and Simon Wilkinson

  10. 1.5.60 open issues • Demand Attach Fileserver bugs (more on that later) • Otherwise, same issues as 1.4.10.

  11. Unix platform round-up • AIX 5 and 6 • FreeBSD 7 and current • HP-UX 11.0, 11i v1 and v2 • Irix 6.5 • Linux 2.2, 2.4, 2.6 (ia32, ia64, x86_64, ppc, ppc64, arm, sparc, sparc64) • MacOS 10.3, 10.4, 10.5. • OpenBSD 4.4, 4.5. • Solaris 2.6, 7, 8, 9, 10, 11 (and OpenSolaris)

  12. MacOS X • Most of the issues with 10.4 were resolved for 10.5 with help from Apple. • However, getting tokens at login is (now) “hard”. • AFSCommander tool available, integration coming. • Sadly, no kexts on the iPhone (It IS just OSX).

  13. Linux • iget() is dead. • Cache manager opens files by path, as in OSX, to deal. • Cache type abstraction. • Changes to avoid deadlocks due to VM system page writeback. • Dynamic sizing for AFS client vnode pool.

  14. AIX • A LAM plugin for Kerberos 5 based aklog is available and works with CDE Screenlock. • The client properly supports AFSDB. • AIX 6 support was contributed by Niklas Edmundsson. • AIX 5.1 will properly support PAGs again in 1.4.11, 1.5.61

  15. BSD • Previous work on FreeBSD had always stumbled on locking issues. • Matt Benjamin revisited, fixed, and updated the previous work. He found the locking issues still lurked. • Further work on OpenBSD and NetBSD has also been done but clients are not as ready.

  16. Clients • Actually not much exciting on clients. • Numerous interaction issues with GUI environments have been addressed. • Notable exception: Finder (more later) • Far fewer resources are leaked during client operation. We’re not perfect yet. • No more gratuitous token disappearance.

  17. Fileservers • The salvager won’t corrupt directories anymore on 64 bit hosts thanks to good sleuthing by Rainer Toebbicke. • Your larger-than-2tb partitions are now good to go. • Old “vos” clients may report odd numbers for empty partitions.

  18. Playing nicely with other children • Quotas enforced on TellMeAboutYourself /WhoAreYou calls to clients will preclude resource hogging. • No more assert()s when a volume is found in an unexpected state. • The server will never keep clients waiting forever for an answer (nor is the client that patient anymore) starting with 1.4.8.

  19. And who were you, again? • Client tracking turns out to be hard when clients lie (unbeknownst to themselves). • Just because an address is reused does not mean it’s the same client. • The fileserver will work even harder to take client address information with a lump of salt.

  20. Things to test in 1.5 • Cache bypass (Linux-only, new since 1.5.53) • Support for additional platforms is also needed. • Split cache (dedicated portion for read-write data). • Early versions of this had corruption issues likely related to writedcache-enforce-xdcache-writelock-20071208 ; thanks to Stephan Weisand for working with me on that (for quite a while).

  21. Features galore • Linux NFS translator still not globally suportable. • GPL-only changes recently break it. • Mountpointless volume addressing (/afs/.:mount/cell:volumeid/) is available. • Originally done for the Linux NFS translator. • An extension allows any vnode to be used. (/afs/.:mountcell:volumeid:vnodeid:uniquifier/)

  22. But now how much would you pay? • Read-write disconnected AFS support. • Cache read-ahead. (Configurable window size, defaults to off) • Tunable with “fs precache”. • And...

  23. Demand Attach Fileserver • Known issues: • Volume headers for non-existent data on disk can remain in memory in a way that does not allow them to be purged. • Several outstanding bugs in RT. • Please share other issues if you have them!

  24. A common theme • We’re (always) looking for volunteers. • Sometimes we are better about asking than others. • Today I will reiterate: please help us test 1.5 (especially DAFS and Disconnected AFS)

  25. Pending integration • Rx K5 • Being revised to match current build trees. • Rx OSD. • Being committed in manageable chunks. • Testing now possible!

  26. More pending work • Extended callback messages to optimize away unneeded traffic. • Both change “ranges” when data is stored, and metadata bundling when other things cause the callback. • Also possible to get finer-than-whole-volume notifications on releases.

  27. Near term undertakings • Locking enhancements for Unix clients. • A fix for the MacOS “Finder cross-volume drag” issue. • A userspace helper and the ad-hoc “reference any vnode” semantics make this simple to solve.

  28. And on the horizon • Multiple volume snapshots. • RxTCP. • Directory object changes (Unicode, typed streams, more files, better hashing). • Full Kerberos 5 support.

  29. On version control • git is coming. • It should be much easier to track upstream as we work with you on integrating your changes. • And it should be easier for us to merge them, too. • More about this will be discussed.

  30. Fresh blood • Google Summer of Code accepted us again. • Summaries available on the OpenAFS website. • More in a moment. • The UIUC Capstone project still working with us. • Their target project is an improved Windows Server Manager application.

  31. Google Summer of Code • Windows MMC management snapin, Brant Gurganus. • Improved OpenAFS server selection, Jake Thebault-Spieker. • OpenAFS features in the Linux kAFS client, Wang Lei.

  32. Google Summer of Code • Last year’s projects offered varying success. • Write support for disconnected AFS. • kAFS pioctl support. • Read-write replication. • Per-file ACL support.

  33. In other news • More during the roadmap discussion. • Oh yeah, got anything for us to debug?

  34. OpenAFS StatusIf your cell phone rang, you owe me a beer.Oh wait, the beer’s free.

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