From: Andi Kleen <andi@firstfloor.org>
To: "Daniel Taylor" <Daniel.Taylor@wdc.com>
Cc: "Mike Fedyk" <mfedyk@mikefedyk.com>,
"Daniel J Blueman" <daniel.blueman@gmail.com>,
"Mat" <jackdachef@gmail.com>,
"LKML" <linux-kernel@vger.kernel.org>,
<linux-fsdevel@vger.kernel.org>,
"Chris Mason" <chris.mason@oracle.com>,
"Ric Wheeler" <rwheeler@redhat.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"The development of BTRFS" <linux-btrfs@vger.kernel.org>
Subject: Re: Btrfs: broken file system design
Date: Fri, 25 Jun 2010 11:15:55 +0200 [thread overview]
Message-ID: <87hbkrealw.fsf@basil.nowhere.org> (raw)
In-Reply-To: <469D2D911E4BF043BFC8AD32E8E30F5B24AEBB@wdscexbe07.sc.wdc.com> (Daniel Taylor's message of "Thu, 24 Jun 2010 15:06:03 -0700")
"Daniel Taylor" <Daniel.Taylor@wdc.com> writes:
>
> As long as no object smaller than the disk block size is ever
> flushed to media, and all flushed objects are aligned to the disk
> blocks, there should be no real performance hit from that.
The question is just how large such a block needs to be.
Traditionally some RAID controllers (and possibly some SSDs now)
needed very large blocks upto MBs.
>
> Otherwise we end up with the damage for the ext[234] family, where
> the file blocks can be aligned, but the 1K inode updates cause
> the read-modify-write (RMW) cycles and and cost >10% performance
> hit for creation/update of large numbers of files.
Fixing that doesn't require a new file system layout, just some effort
to read/write inodes in batches of multiple of them. XFS did similar
things for a long time, I believe there were some efforts for this
for ext4 too.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-06-25 9:15 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-03 14:58 Unbound(?) internal fragmentation in Btrfs Edward Shishkin
[not found] ` <AANLkTilKw2onQkdNlZjg7WVnPu2dsNpDSvoxrO_FA2z_@mail.gmail.com>
2010-06-18 8:03 ` Christian Stroetmann
2010-06-18 13:32 ` Btrfs: broken file system design (was Unbound(?) internal fragmentation in Btrfs) Edward Shishkin
2010-06-18 13:45 ` Daniel J Blueman
2010-06-18 16:50 ` Edward Shishkin
2010-06-23 23:40 ` Jamie Lokier
2010-06-24 3:43 ` Daniel Taylor
2010-06-24 4:51 ` Mike Fedyk
2010-06-24 22:06 ` Daniel Taylor
2010-06-25 9:15 ` Andi Kleen [this message]
2010-06-25 18:58 ` Ric Wheeler
2010-06-26 5:18 ` Michael Tokarev
2010-06-26 11:55 ` Ric Wheeler
[not found] ` <57784.2001:5c0:82dc::2.1277555665.squirrel@www.tofubar.com>
2010-06-26 13:47 ` Ric Wheeler
2010-06-24 9:50 ` David Woodhouse
2010-06-18 18:15 ` Christian Stroetmann
2010-06-18 13:47 ` Chris Mason
2010-06-18 15:05 ` Edward Shishkin
[not found] ` <4C1B8B4A.9060308@gmail.com>
2010-06-18 15:10 ` Chris Mason
2010-06-18 16:22 ` Edward Shishkin
[not found] ` <4C1B9D4F.6010008@gmail.com>
2010-06-18 18:10 ` Chris Mason
2010-06-18 15:21 ` Christian Stroetmann
2010-06-18 15:22 ` Chris Mason
2010-06-18 15:56 ` Jamie Lokier
2010-06-18 19:25 ` Christian Stroetmann
2010-06-18 19:29 ` Edward Shishkin
2010-06-18 19:35 ` Chris Mason
2010-06-18 22:04 ` Balancing leaves when walking from top to down (was Btrfs:...) Edward Shishkin
[not found] ` <4C1BED56.9010300@redhat.com>
2010-06-18 22:16 ` Ric Wheeler
2010-06-19 0:03 ` Edward Shishkin
2010-06-21 13:15 ` Chris Mason
[not found] ` <20100621180013.GD17979@think>
2010-06-22 14:12 ` Edward Shishkin
2010-06-22 14:20 ` Chris Mason
2010-06-23 13:46 ` Edward Shishkin
[not found] ` <4C221049.501@gmail.com>
2010-06-23 23:37 ` Jamie Lokier
2010-06-24 13:06 ` Chris Mason
2010-06-30 20:05 ` Edward Shishkin
[not found] ` <4C2BA381.7040808@redhat.com>
2010-06-30 21:12 ` Chris Mason
2010-07-09 4:16 ` Chris Samuel
2010-07-09 20:30 ` Chris Mason
2010-06-23 23:57 ` Btrfs: broken file system design (was Unbound(?) internal fragmentation in Btrfs) Jamie Lokier
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