Date: Mon, 25 May 2026 11:01:42 +0300 From: Daniel Braniss <danny@cs.huji.ac.il> To: Rick Macklem <rick.macklem@gmail.com> Cc: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net>, Freebsd-stable List <stable@freebsd.org> Subject: Re: 15.1 diskless hangs Message-ID: <0ED1A6F2-3454-4DA0-BF32-78016DB39C97@cs.huji.ac.il> In-Reply-To: <CAM5tNy5ySLycbMtapbW%2BFG9DNqoveh7OdRKDBDmBxDP406Y7FA@mail.gmail.com> References: <6D7CAB2A-7308-457F-9925-DBAD476B8E3F@cs.huji.ac.il> <42ns45s-94s2-32s2-710-41oprnp719q@mnoonqbm.arg> <F13383B9-44CA-49C2-A593-AB0116135F61@cs.huji.ac.il> <CAM5tNy5ySLycbMtapbW%2BFG9DNqoveh7OdRKDBDmBxDP406Y7FA@mail.gmail.com>
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[-- Attachment #1 --] > On 22 May 2026, at 15:38, Rick Macklem <rick.macklem@gmail.com> wrote: > > On Thu, May 21, 2026 at 10:24 PM Daniel Braniss <danny@cs.huji.ac.il <mailto:danny@cs.huji.ac.il>> wrote: >> >> >> >>> On 21 May 2026, at 22:02, Bjoern A. Zeeb <bzeeb-lists@lists.zabbadoz.net> wrote: >>> >>> On Thu, 21 May 2026, Daniel Braniss wrote: >>> >>>> have several bhives and my workstation, running diskless, the server is also freebsd, >>>> and very often, they hang on nfs, (I assume trying to access the root). >>>> having them boot locally, and everything else, ie. /usr/local, home directory are nfs mounted without issues. >>>> >>>> i’ll try and do a tcpdump but in the meantime any isights are welcome. >>> >>> When do they hang? During boot? Or during operation? >> >> during normal operation. >>> >>> If they hang on an interactive command try ^T and see. >> >> since root is nfs mounted, and it’s hung, nothing but power cycling works. >>> >>> If tcpdump doesn't help much I'd start turning off checksum offloads and the like >>> along the path (unclear if your host is your nfs server or not) to see if that helps. >> >> some more info: >> the server is running 14.3 (i don’t think this is relevant) >> the server us also providing /usr/local >> if the host is running with a local root, all is fine. >> virtual hosts, i.e bhive, also hang under similar configuration. >> >> so now i'm running a tcpdump on the server, and will probably have more info. > That should give you more information. A few things to note: > - 15.1 has the capability of using NFSv4 for root, but that requires some > careful configuration. > - Assuming your root is NFSv3 (you'll see that in the packet capture > in wireshark), make sure you are not running nfsuserd(8) or gssd(8). only NFS3 > Both of these will try and look up user/group names in the passwd/group > file and this can hang the system when they do the upcall from within > the NFS client (which would have to access the files). > > rick so it hanged, im attaching the relevant tcpdump, what is weird, and I must have forgotten much, nrnd is the server, chamsa is the client. it seems nrnd is requesting arp too often … is the TTL on the arp reseted when a packet is received, or it just times out? here is the abridged version: > >> >> thanks, >> danny >> >>> >>> /bz >>> >>> -- >>> Bjoern A. Zeeb r15:7 [-- Attachment #2 --]home | help
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