linux-kernel - Re: ATA 4 KiB sector issues.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4B963351.50707@msgid.tls.msk.ru>
Date:	Tue, 09 Mar 2010 14:38:57 +0300
From:	Michael Tokarev <mjt@....msk.ru>
To:	Dave Chinner <david@...morbit.com>
CC:	Karel Zak <kzak@...hat.com>, Mike Snitzer <snitzer@...hat.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	Tejun Heo <tj@...nel.org>,
	"linux-ide@...r.kernel.org" <linux-ide@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	Daniel Taylor <Daniel.Taylor@....com>,
	Jeff Garzik <jeff@...zik.org>, Mark Lord <kernel@...savvy.com>,
	tytso@....edu, "H. Peter Anvin" <hpa@...or.com>,
	hirofumi@...l.parknet.co.jp,
	Andrew Morton <akpm@...ux-foundation.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>, irtiger@...il.com,
	Matthew Wilcox <matthew@....cx>, aschnell@...e.de,
	knikanth@...e.de, jdelvare@...e.de,
	Jim Meyering <jim@...ering.net>, Neil Brown <neilb@...e.de>
Subject: Re: ATA 4 KiB sector issues.

Dave Chinner wrote:
> On Tue, Mar 09, 2010 at 01:16:01PM +0300, Michael Tokarev wrote:
>> Karel Zak wrote:
>>> I did almost all my tests with scsi_debug or MD RAID0 on scsi_debug.
>>> It works as expected.
>> Actually, for raid0, the alignment is questionable.  Should it be a
>> multiple of chunk size or whole stripe size?  I'm not sure, both ways
>> has bad and good sides..  But if it is the latter, the same issues
>> pops up again: do a 3-disk raid0 and you'll have to align to 3*2^N.
> 
> Yes, alignment is still needed, especially for filesystems that can
> do stripe unit aligned allocation like XFS. If you don't align the
> filesystem properly, all the data IO will be mis-aligned to the
> underlying disks and stripe unit sized IO will hit multiple disks
> rather than just one....

I understand alignment is needed, the question is if the alignment
should be to chunk size or full-stripe size.  In neither case it
will be bad for underlying disks.

/mjt
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/