From: Lionel Cons <lionelcons1972@gmail.com>
To: linux-nfs <linux-nfs@vger.kernel.org>
Subject: Re: Suggestions to drastically reduce Linux nfsd I/O latency on BTRFS?
Date: Tue, 12 May 2026 16:52:34 +0200 [thread overview]
Message-ID: <CAPJSo4UFrWbuC1hKNg8oxnJtSZAE=xEVv5T_UfuSOP1uZgeQEA@mail.gmail.com> (raw)
In-Reply-To: <e44aa868-5ec8-4c35-b5bc-5066487a28be@app.fastmail.com>
On Tue, 12 May 2026 at 15:23, Chuck Lever <cel@kernel.org> wrote:
>
>
> On Tue, May 12, 2026, at 5:47 AM, Lionel Cons wrote:
> > Are there suggestions on how to reduce Linux nfsd I/O latency on
> > BTRFS?
>
> For us mere humans, the first step is you need to root-cause
> your issue. But consider using an LLM to help you with this
> process.
>
> Example questions to guide your analysis:
> - What particular NFS operations are taking too long?
Read, Write, issued to serve single-file disk images with bhyve and qemu
> - How full is your exported file system?
9% full, 2 PiB total size
> - What backing storage is in use, and what mount options?
Very, very big hardware RAID0 with battery-backed ram cache, shows up
as one single SCSI disk
> - What transport (TCP? RDMA?)
TCP6
> - How much server CPU is available when the it appears slow?
64 CPU cores, 512GB RAM
> - If you are using NFSv4, are there other clients that emit
> conflicting OPENs and LOCKs?
No, just read and write are slower, compared to doing the same setup
with something like ISCSI.
Lionel
prev parent reply other threads:[~2026-05-12 14:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-12 9:47 Suggestions to drastically reduce Linux nfsd I/O latency on BTRFS? Lionel Cons
2026-05-12 13:22 ` Chuck Lever
2026-05-12 14:52 ` Lionel Cons [this message]
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