From: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
To: Pavel Machek <pavel@ucw.cz>
Cc: Ric Wheeler <ricwheeler@gmail.com>, Howard Chu <hyc@symas.com>,
"Theodore Ts'o" <tytso@mit.edu>, Chinmay V S <cvs268@gmail.com>,
Stefan Priebe - Profihost AG <s.priebe@profihost.ag>,
Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: Why is O_DSYNC on linux so slow / what's wrong with my SSD?
Date: Sun, 24 Nov 2013 01:03:16 +0000 [thread overview]
Message-ID: <20131124010316.2ca6a8ce@alan.etchedpixels.co.uk> (raw)
In-Reply-To: <20131124002236.GA10600@amd.pavel.ucw.cz>
> Yes, and I'm arguing that is a bug (as in, < 0.01% people are using
> hdparm correctly).
Generally speaking if you are using hdparm for tuning it means we need to
fix something in the ATA layer so you don't have to !
> I guess it would be safer not to reattach drives after power
> fail... (also I wonder what this does to data integrity. Drive lost
> content of its writeback cache, but kernel continues... Journal will
> not prevent data corruption in this case).
For good or bad its very hard to tell if a drive randomly powers off or
we merely get a bus reset in the ATA case. In the SATA case we do at
least get the relevant events to handle it nicely as we *should* see a
DevExch event. We also can't tell a power fail event from a hot drive
swap, so we most definitely want to re-attach the drive, just so long as
we ensure that it comes back on a different device node.
Alan
next prev parent reply other threads:[~2013-11-24 1:03 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-20 12:12 Why is O_DSYNC on linux so slow / what's wrong with my SSD? Stefan Priebe - Profihost AG
2013-11-20 12:54 ` Christoph Hellwig
2013-11-20 13:34 ` Chinmay V S
2013-11-20 13:38 ` Christoph Hellwig
2013-11-20 14:12 ` Stefan Priebe - Profihost AG
2013-11-20 15:22 ` Chinmay V S
2013-11-20 15:37 ` Theodore Ts'o
2013-11-20 15:55 ` J. Bruce Fields
2013-11-20 17:11 ` Chinmay V S
2013-11-20 17:58 ` J. Bruce Fields
2013-11-20 18:43 ` Chinmay V S
2013-11-21 10:11 ` Christoph Hellwig
2013-11-22 20:01 ` Stefan Priebe
2013-11-22 20:37 ` Ric Wheeler
2013-11-22 21:05 ` Stefan Priebe
2013-11-23 18:27 ` Stefan Priebe
2013-11-23 19:35 ` Ric Wheeler
2013-11-23 19:48 ` Stefan Priebe
2013-11-25 7:37 ` Stefan Priebe
2020-01-08 6:58 ` slow sync performance on LSI / Broadcom MegaRaid performance with battery cache Stefan Priebe - Profihost AG
2013-11-22 19:57 ` Why is O_DSYNC on linux so slow / what's wrong with my SSD? Stefan Priebe
2013-11-24 0:10 ` One Thousand Gnomes
2013-11-20 16:02 ` Howard Chu
2013-11-23 20:36 ` Pavel Machek
2013-11-23 23:01 ` Ric Wheeler
2013-11-24 0:22 ` Pavel Machek
2013-11-24 1:03 ` One Thousand Gnomes [this message]
2013-11-24 2:43 ` Ric Wheeler
2013-11-22 19:55 ` Stefan Priebe
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