From: Martin <m_btrfs@ml1.co.uk>
To: linux-btrfs@vger.kernel.org
Subject: Re: btrfs and 1 billion small files
Date: Tue, 08 May 2012 17:51:05 +0100 [thread overview]
Message-ID: <jobitp$lju$1@dough.gmane.org> (raw)
In-Reply-To: <20120508123153.GS11876@shiny>
On 08/05/12 13:31, Chris Mason wrote:
[...]
> A few people have already mentioned how btrfs will pack these small
> files into metadata blocks. If you're running btrfs on a single disk,
[...]
> But the cost is increased CPU usage. Btrfs hits memmove and memcpy
> pretty hard when you're using larger blocks.
>
> I suggest using a 16K or 32K block size. You can go up to 64K, it may
> work well if you have beefy CPUs. Example for 16K:
>
> mkfs.btrfs -l 16K -n 16K /dev/xxx
Is that still with "-s 4K" ?
Might that help SSDs that work in 16kByte chunks?
And why are memmove and memcpy more heavily used?
Does that suggest better optimisation of the (meta)data, or just a
greater housekeeping overhead to shuffle data to new offsets?
Regards,
Martin
next prev parent reply other threads:[~2012-05-08 16:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1913174825.1910.1336382310577.JavaMail.root@zimbra.interconnessioni.it>
2012-05-07 9:28 ` btrfs and 1 billion small files Alessio Focardi
2012-05-07 9:58 ` Hubert Kario
2012-05-07 10:06 ` Boyd Waters
2012-05-08 6:31 ` Chris Samuel
2012-05-07 10:55 ` Hugo Mills
2012-05-07 11:15 ` Alessio Focardi
2012-05-07 11:39 ` Hugo Mills
2012-05-07 12:19 ` Johannes Hirte
2012-05-07 11:05 ` vivo75
2012-05-08 16:46 ` Martin
2012-05-07 15:13 ` David Sterba
2012-05-08 12:31 ` Chris Mason
2012-05-08 16:51 ` Martin [this message]
2012-05-08 20:54 ` Chris Mason
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='jobitp$lju$1@dough.gmane.org' \
--to=m_btrfs@ml1.co.uk \
--cc=linux-btrfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.