From: Rik Theys <Rik.Theys@esat.kuleuven.be>
To: Rick Macklem <rick.macklem@gmail.com>
Cc: Benjamin Coddington <ben.coddington@hammerspace.com>,
Linux Nfs <linux-nfs@vger.kernel.org>
Subject: Re: NFS4ERR_SEQ_MISORDERED errors and NFS client very slow
Date: Thu, 30 Apr 2026 17:03:50 +0200 [thread overview]
Message-ID: <58dc67a1-49a4-41ab-97ba-5a4f295cde1f@esat.kuleuven.be> (raw)
In-Reply-To: <CAM5tNy6j0JhZ8yM1T_bT3pddBi21Q3JN-qnsMN8K5mn7KQdeiw@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 2511 bytes --]
Hi,
On 4/30/26 4:39 PM, Rick Macklem wrote:
> On Thu, Apr 30, 2026 at 7:26 AM Rik Theys <Rik.Theys@esat.kuleuven.be> wrote:
>> Hi Benjamin,
>>
>> On 4/30/26 3:27 PM, Benjamin Coddington wrote:
>>> On 30 Apr 2026, at 2:53, Rik Theys wrote:
>>>
>>>> Hi,
>>>>
>>>> We have a Rocky 8 client running Linux 7.0.2 (kernel-ml from elrepo) that is an NFS client to a RHEL10 server.
>>>>
>>>> Lately we've noticed that NFS performance is very poor for certain workloads (We saw the same issue on the stock EL8 kernel, 6.18.20 and now 7.0.2). For example cloning git repositories is extremely slow.
>>>>
>>>> Looking at the server side there don't seem to be any saturations of the disk or network subsystems.
>>>>
>>>> I've taken a network dump between the client and server. In that dump I see that the server frequently responds to requests from the client with NFS4ERR_SEQ_MISORDERED (10063). What could be the cause of these mismatches? Is this always a client issue, or can this be caused by the server?
>>> This is something you shouldn't normally see and probably indicates a bug or
>>> serious problem. From the client side you'd only expect this if you're
>>> doing a lot of task signaling so that the userland processes abandon RPCs.
>> Would there be any indications in the logs if this is the case?
>>
>>
>>> A packet capture is the best way to determine if the server is mis-reporting
>>> the sequencing problem, or if the client's sequencing is incorrect. Given
>>> your description of the symptoms I'd also check to make sure your underlying
>>> network isn't doing something totally nuts like duplicating packets.
>> My previous capture was on the client, which is where I observed the
>> NFS4ERR_SEQ_MISORDERED messages. I've now taken a capture on the server
>> and there I do see some duplicate packets, but not a large percentage.
>> Should the NFS server not notice this is a duplicate packet and ignore it?
> TCP will normally deal with duplicate TCP segments.
>
> What I think Benjamin was referring to is an entire RPC request message
> being duplicated, with the same seq# in the SEQUENCE operation at the
> beginning of the RPC.
I've attached (part of) the capture. Which fields should I check?
Regards,
Rik
--
Rik Theys
System Engineer
KU Leuven - Dept. Elektrotechniek (ESAT)
Kasteelpark Arenberg 10 bus 2440 - B-3001 Leuven-Heverlee
+32(0)16/32.11.07
----------------------------------------------------------------
<<Any errors in spelling, tact or fact are transmission errors>>
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next prev parent reply other threads:[~2026-04-30 15:04 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-30 6:53 NFS4ERR_SEQ_MISORDERED errors and NFS client very slow Rik Theys
2026-04-30 13:27 ` Benjamin Coddington
2026-04-30 14:26 ` Rik Theys
2026-04-30 14:34 ` Rick Macklem
2026-04-30 14:39 ` Rick Macklem
2026-04-30 15:03 ` Rik Theys [this message]
2026-04-30 15:02 ` Rick Macklem
2026-04-30 15:27 ` Rik Theys
2026-04-30 15:35 ` Rick Macklem
2026-04-30 16:24 ` Rick Macklem
2026-04-30 17:04 ` Rik Theys
2026-04-30 17:29 ` Olga Kornievskaia
2026-04-30 18:08 ` Rik Theys
2026-04-30 18:28 ` Olga Kornievskaia
2026-05-04 7:30 ` Rik Theys
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