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From: Qu Wenruo <quwenruo.btrfs@gmx.com>
To: "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	linux-block@vger.kernel.org
Subject: Is it possible that certain physical disk doesn't implement flush correctly?
Date: Sat, 30 Mar 2019 20:31:08 +0800	[thread overview]
Message-ID: <dc1735e6-e410-e593-7059-3728eb427886@gmx.com> (raw)


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Hi,

I'm wondering if it's possible that certain physical device doesn't
handle flush correctly.

E.g. some vendor does some complex logical in their hdd controller to
skip certain flush request (but not all, obviously) to improve performance?

Do anyone see such reports?

And if proves to happened before, how do we users detect such problem?

Can we just check the flush time against the write before flush call?
E.g. write X random blocks into that device, call fsync() on it, check
the execution time. Repeat Y times, and compare the avg/std.
And change X to 2X/4X/..., repeat above check.

Thanks,
Qu



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             reply	other threads:[~2019-03-30 12:31 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-30 12:31 Qu Wenruo [this message]
2019-03-30 12:57 ` Is it possible that certain physical disk doesn't implement flush correctly? Supercilious Dude
2019-03-30 13:00   ` Qu Wenruo
2019-03-30 13:04     ` Supercilious Dude
2019-03-30 13:09       ` Qu Wenruo
2019-03-30 13:14         ` Supercilious Dude
2019-03-30 13:24           ` Qu Wenruo
2019-03-31 22:45             ` J. Bruce Fields
2019-03-31 23:07               ` Alberto Bursi
2019-03-31 11:27 ` Alberto Bursi
2019-03-31 12:00   ` Qu Wenruo
2019-03-31 13:36     ` Hannes Reinecke
2019-03-31 14:17       ` Qu Wenruo
2019-03-31 14:37         ` Hannes Reinecke
2019-03-31 14:40           ` Qu Wenruo
2019-03-31 12:21   ` Andrei Borzenkov
2019-04-01 11:55   ` Austin S. Hemmelgarn
2019-04-01 12:04 ` Austin S. Hemmelgarn

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