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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: Chuck Lever <chuck.lever@oracle.com>,
	Christoph Hellwig <hch@infradead.org>,
	Dave Chinner <david@fromorbit.com>,
	Anna Schumaker <anna.schumaker@oracle.com>,
	lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Implementing the NFS v4.2 WRITE_SAME operation: VFS or NFS ioctl() ?
Date: Thu, 16 Jan 2025 17:11:42 -0500	[thread overview]
Message-ID: <yq17c6uzao3.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <20250116173000.GA2479310@mit.edu> (Theodore Ts'o's message of "Thu, 16 Jan 2025 12:30:00 -0500")


Hi Ted!

>    * DIF/DIX (although this is super expensive, so this has fallen out
>         of favor)

Several cloud providers use T10 PI-capable storage in their backend. The
interface is rarely exposed to customers, though.

>    * In-line checksums in the database block; this approach is fairly
>         common for enterprise databases

Yep.

Also note that DIX/T10 PI are intended to prevent writing corrupted
buffers or misdirected data to media. I.e. at WRITE time. Neither DIX,
nor T10 PI offer any torn write guarantees. That's what the dedicated
atomic write operations are for (and those do support PI).

In-line application block checksums are a solution for the problem of
determining whether a database block read from media is intact. I.e.
in-line checksums are effective at READ time.

-- 
Martin K. Petersen	Oracle Linux Engineering

  reply	other threads:[~2025-01-16 22:12 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-14 21:38 [LSF/MM/BPF TOPIC] Implementing the NFS v4.2 WRITE_SAME operation: VFS or NFS ioctl() ? Anna Schumaker
2025-01-14 23:14 ` Dave Chinner
2025-01-16  5:42   ` Christoph Hellwig
2025-01-16 13:37     ` Theodore Ts'o
2025-01-16 13:59       ` Chuck Lever
2025-01-16 15:36         ` Theodore Ts'o
2025-01-16 15:45           ` Chuck Lever
2025-01-16 17:30             ` Theodore Ts'o
2025-01-16 22:11               ` Martin K. Petersen [this message]
2025-01-16 21:54             ` [Lsf-pc] " Martin K. Petersen
2025-01-15  2:10 ` Darrick J. Wong
2025-01-15 14:24 ` Jeff Layton
2025-01-15 15:06 ` Matthew Wilcox
2025-01-15 15:31   ` Chuck Lever
2025-01-15 16:19     ` Matthew Wilcox
2025-01-15 18:20       ` Darrick J. Wong
2025-01-15 18:43       ` Chuck Lever
2025-01-16  5:40 ` Christoph Hellwig

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