From: Jaegeuk Kim <jaegeuk.kim@gmail.com>
To: Namjae Jeon <linkinjeon@gmail.com>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>,
Arnd Bergmann <arnd@arndb.de>,
David Woodhouse <dwmw2@infradead.org>,
Luk Czerner <lczerner@redhat.com>,
Vyacheslav Dubeyko <slava@dubeyko.com>,
Marco Stornelli <marco.stornelli@gmail.com>,
Al Viro <viro@zeniv.linux.org.uk>,
tytso@mit.edu, gregkh@linuxfoundation.org,
linux-kernel@vger.kernel.org, chur.lee@samsung.com,
cm224.lee@samsung.com, jooyoung.hwang@samsung.com,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 00/16] f2fs: introduce flash-friendly file system
Date: Sat, 13 Oct 2012 21:37:20 +0900 [thread overview]
Message-ID: <1350131840.1917.53.camel@kjgkr> (raw)
In-Reply-To: <CAKYAXd99LRV0VqpGRKxBnDd7MORkLJScZ7M5k14sZmxz-uS-Gw@mail.gmail.com>
2012-10-13 (토), 13:26 +0900, Namjae Jeon:
> Is there high possibility that the storage device can be rapidly
> worn-out by cleaning process ? e.g. severe fragmentation situation by
> creating and removing small files.
>
Yes, the cleaning process in F2FS induces additional writes so that
flash storage can be worn out quickly.
However, how about in traditonal file systems?
As all of us know that, FTL has an wear-leveling issue too due to the
garbage collection overhead that is fundamentally similar to the
cleaning overhead in LFS or F2FS.
So, what's the difference between them?
IMHO, the major factor to reduce the cleaning or garbage collection
overhead is how to efficiently separate hot and cold data.
So, which is a better layer between FTL and file system to achieve that?
I think the answer is the file system, since the file system has much
more information on such a hotness of all the data, but FTL doesn't know
or is hard to figure out that kind of information.
Therefore, I think the LFS approach is more beneficial to span the life
time of the storage rather than traditional one.
And, in order to do this perfectly, one thing is a criteria, the
alignment between FTL and F2FS.
> And you told us only advantages of f2fs. Would you tell us the disadvantages ?
I think there is a scenario like this.
1) One big file is created and written data sequentially.
2) Many random writes are done across the whole file range.
3) User discards cached data by doing "drop_caches" or "reboot".
At this point, I worry about the sequential read performance due to the
fragmentation.
I don't know how frequently this use-case happens, but it is one of cons
in the LFS approach.
Nevertheless, I'm thinking that the performance could be enhanced by
cooperating with a readahead mechanism in VFS.
Thanks,
>
> Thanks.
--
Jaegeuk Kim
Samsung
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next prev parent reply other threads:[~2012-10-13 12:37 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <415E76CC-A53D-4643-88AB-3D7D7DC56F98@dubeyko.com>
2012-10-06 13:54 ` [PATCH 00/16] f2fs: introduce flash-friendly file system Vyacheslav Dubeyko
2012-10-06 20:06 ` Jaegeuk Kim
2012-10-07 7:09 ` Marco Stornelli
2012-10-07 9:31 ` Jaegeuk Kim
2012-10-07 12:08 ` Vyacheslav Dubeyko
2012-10-08 8:25 ` Jaegeuk Kim
2012-10-08 9:59 ` Namjae Jeon
2012-10-08 10:52 ` Jaegeuk Kim
2012-10-08 11:21 ` Namjae Jeon
2012-10-08 12:11 ` Jaegeuk Kim
2012-10-09 3:52 ` Namjae Jeon
2012-10-09 8:00 ` Jaegeuk Kim
2012-10-09 8:31 ` Lukáš Czerner
2012-10-09 10:45 ` Jaegeuk Kim
2012-10-09 11:01 ` Lukáš Czerner
2012-10-09 12:01 ` Jaegeuk Kim
2012-10-09 12:39 ` Lukáš Czerner
2012-10-09 13:10 ` Jaegeuk Kim
2012-10-09 21:20 ` Dave Chinner
2012-10-10 2:32 ` Jaegeuk Kim
2012-10-10 4:53 ` Theodore Ts'o
2012-10-12 20:55 ` Arnd Bergmann
2012-10-10 10:36 ` David Woodhouse
2012-10-12 20:58 ` Arnd Bergmann
2012-10-13 4:26 ` Namjae Jeon
2012-10-13 12:37 ` Jaegeuk Kim [this message]
2012-10-17 11:12 ` Namjae Jeon
[not found] ` <000001cdacef$b2f6eaa0$18e4bfe0$%kim@samsung.com>
2012-10-18 13:39 ` Vyacheslav Dubeyko
2012-10-18 22:14 ` Jaegeuk Kim
2012-10-19 9:20 ` NeilBrown
2012-10-08 19:22 ` Vyacheslav Dubeyko
2012-10-09 7:08 ` Jaegeuk Kim
2012-10-09 19:53 ` Jooyoung Hwang
2012-10-10 8:05 ` Vyacheslav Dubeyko
2012-10-10 9:02 ` Theodore Ts'o
2012-10-10 11:52 ` SQLite on flash (was: [PATCH 00/16] f2fs: introduce flash-friendly file system) Clemens Ladisch
[not found] ` <50756199.1090103-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>
2012-10-10 12:47 ` Richard Hipp
2012-10-10 17:17 ` light weight write barriers Andi Kleen
[not found] ` <m2fw5mtffg.fsf_-_-Vw/NltI1exuRpAAqCnN02g@public.gmane.org>
2012-10-10 17:48 ` Richard Hipp
[not found] ` <CALwJ=MyR+nU3zqi3V3JMuEGNwd8FUsw9xLACJvd0HoBv3kRi0w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-11 16:38 ` Nico Williams
[not found] ` <CAK3OfOi3E1ePfzWjq1epFaXsjtn8V_=r3h+PG6ankWW2fOr6GA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-11 16:48 ` Nico Williams
2012-10-11 16:32 ` 杨苏立 Yang Su Li
2012-10-11 17:41 ` [sqlite] " Christoph Hellwig
2012-10-23 19:53 ` Vladislav Bolkhovitin
[not found] ` <5086F5A7.9090406-d+Crzxg7Rs0@public.gmane.org>
2012-10-24 21:17 ` Nico Williams
2012-10-24 22:03 ` [sqlite] " david
[not found] ` <alpine.DEB.2.02.1210241447210.8519-Z4YwzcCRHZnr5h6Zg1Auow@public.gmane.org>
2012-10-25 0:20 ` Nico Williams
2012-10-25 1:04 ` [sqlite] " david
[not found] ` <alpine.DEB.2.02.1210241748180.8519-Z4YwzcCRHZnr5h6Zg1Auow@public.gmane.org>
2012-10-25 5:18 ` Nico Williams
2012-10-25 6:02 ` [sqlite] " Theodore Ts'o
2012-10-25 6:58 ` david
[not found] ` <alpine.DEB.2.02.1210242331060.31862-Z4YwzcCRHZnr5h6Zg1Auow@public.gmane.org>
2012-10-25 14:03 ` Theodore Ts'o
[not found] ` <20121025140327.GB13562-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2012-10-25 18:03 ` david-gFPdbfVZQbY
[not found] ` <alpine.DEB.2.02.1210251048280.8519-Z4YwzcCRHZnr5h6Zg1Auow@public.gmane.org>
2012-10-25 18:29 ` Theodore Ts'o
2012-11-05 20:03 ` [sqlite] " Pavel Machek
[not found] ` <20121105200348.GB15821-5NIqAleC692hcjWhqY66xCZi+YwRKgec@public.gmane.org>
2012-11-05 22:04 ` Theodore Ts'o
[not found] ` <20121105220440.GB25378-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2012-11-05 22:37 ` Richard Hipp
[not found] ` <CALwJ=Mx-uEFLXK2wywekk=0dwrwVFb68wocnH9bjXJmHRsJx3w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-11-05 23:00 ` Theodore Ts'o
2012-10-30 23:49 ` [sqlite] " Nico Williams
2012-10-25 5:42 ` Theodore Ts'o
2012-10-25 7:11 ` david
2012-10-27 1:52 ` Vladislav Bolkhovitin
2012-10-25 5:14 ` Theodore Ts'o
2012-10-25 13:03 ` Alan Cox
[not found] ` <20121025140325.49cd7c79-38n7/U1jhRXW96NNrWNlrekiAK3p4hvP@public.gmane.org>
2012-10-25 13:50 ` Theodore Ts'o
2012-10-27 1:55 ` [sqlite] " Vladislav Bolkhovitin
2012-10-27 1:54 ` Vladislav Bolkhovitin
[not found] ` <508B3EED.2080003-d+Crzxg7Rs0@public.gmane.org>
2012-10-27 4:44 ` Theodore Ts'o
2012-10-30 22:22 ` [sqlite] " Vladislav Bolkhovitin
[not found] ` <5090532D.4050902-d+Crzxg7Rs0@public.gmane.org>
2012-10-31 9:54 ` Alan Cox
2012-11-01 20:18 ` [sqlite] " Vladislav Bolkhovitin
[not found] ` <5092D90F.7020105-d+Crzxg7Rs0@public.gmane.org>
2012-11-01 21:24 ` Alan Cox
2012-11-02 0:15 ` [sqlite] " Vladislav Bolkhovitin
[not found] ` <20121101212418.140e3a82-38n7/U1jhRXW96NNrWNlrekiAK3p4hvP@public.gmane.org>
2012-11-02 0:38 ` Howard Chu
[not found] ` <50931601.4060102-aQkYFu9vm6AAvxtiuMwx3w@public.gmane.org>
2012-11-02 12:24 ` Richard Hipp
2012-11-13 3:41 ` [sqlite] " Vladislav Bolkhovitin
2012-11-02 12:33 ` Alan Cox
2012-11-13 3:41 ` [sqlite] " Vladislav Bolkhovitin
[not found] ` <50A1C15E.2080605-d+Crzxg7Rs0@public.gmane.org>
2012-11-13 17:40 ` Alan Cox
[not found] ` <20121113174000.6457a68b-38n7/U1jhRXW96NNrWNlrekiAK3p4hvP@public.gmane.org>
2012-11-13 19:13 ` Nico Williams
2012-11-15 1:17 ` [sqlite] " Vladislav Bolkhovitin
[not found] ` <50A442AF.9020407-d+Crzxg7Rs0@public.gmane.org>
2012-11-15 12:07 ` David Lang
[not found] ` <alpine.DEB.2.02.1211150353080.32408-UEhY+ZBZOcqqLGM74eQ/YA@public.gmane.org>
2012-11-15 16:14 ` 杨苏立 Yang Su Li
2012-11-17 5:02 ` [sqlite] " Vladislav Bolkhovitin
2012-11-16 15:06 ` Howard Chu
2012-11-16 15:31 ` [sqlite] " Ric Wheeler
[not found] ` <50A65C68.6080001-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-11-16 15:54 ` Howard Chu
2012-11-16 18:03 ` [sqlite] " Ric Wheeler
[not found] ` <50A65681.8000204-aQkYFu9vm6AAvxtiuMwx3w@public.gmane.org>
2012-11-16 19:14 ` David Lang
2012-11-17 5:02 ` [sqlite] " Vladislav Bolkhovitin
2012-11-15 17:06 ` Ryan Johnson
2012-11-15 22:35 ` [sqlite] " Chris Friesen
2012-11-17 5:02 ` Vladislav Bolkhovitin
2012-11-20 1:23 ` Vladislav Bolkhovitin
2012-11-26 20:05 ` Nico Williams
[not found] ` <CAK3OfOjD4XBGfu3cnMwTvCfec0Lvg3zrO16+pXtiFF4UWpFjDw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-11-29 2:15 ` Vladislav Bolkhovitin
2012-11-15 1:16 ` [sqlite] " Vladislav Bolkhovitin
2012-11-13 3:37 ` Vladislav Bolkhovitin
2012-11-11 4:25 ` 杨苏立 Yang Su Li
2012-11-13 3:42 ` [sqlite] " Vladislav Bolkhovitin
2012-10-10 7:57 ` [PATCH 00/16] f2fs: introduce flash-friendly file system Vyacheslav Dubeyko
2012-10-10 9:43 ` Jaegeuk Kim
2012-10-11 3:14 ` Namjae Jeon
[not found] ` <CAN863PuyMkSZtZCvqX+kwei9v=rnbBYVYr3TqBXF_6uxwJe2_Q@mail.gmail.com>
2012-10-17 11:13 ` Namjae Jeon
2012-10-17 23:06 ` Changman Lee
2012-10-12 12:30 ` Vyacheslav Dubeyko
2012-10-12 14:25 ` Jaegeuk Kim
2012-10-07 10:15 ` Vyacheslav Dubeyko
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