From: Adam Brenner <adam@aeb.io>
To: linux-btrfs@vger.kernel.org
Subject: Slow Write Performance w/ No Cache Enabled and Different Size Drives
Date: Sun, 20 Apr 2014 10:27:03 -0700 [thread overview]
Message-ID: <53540367.4050707@aeb.io> (raw)
Howdy,
I recently setup a new BTRFS filesystem based on BTRFS version 3.12 on
Linux kernel 3.13-1 running Debian Jessie.
The BTRFS volume spans 3x 4TB disks, two of which are using the entire
raw block device, and one of them is using a partition (OS disks). The
setup is like so:
root@gra-dfs:/data/tmp# btrfs filesystem show
Label: none uuid: 63d51c9b-f851-404f-b0f2-bf84d07df163
Total devices 3 FS bytes used 3.03TiB
devid 1 size 3.61TiB used 1.01TiB path /dev/sda3
devid 2 size 3.64TiB used 1.04TiB path /dev/sdb
devid 3 size 3.64TiB used 1.04TiB path /dev/sdc
Btrfs v3.12
root@gra-dfs:/data/tmp# btrfs filesystem df /data
Data, single: total=3.07TiB, used=3.03TiB
System, RAID1: total=8.00MiB, used=352.00KiB
System, single: total=4.00MiB, used=0.00
Metadata, RAID1: total=5.00GiB, used=3.60GiB
Metadata, single: total=8.00MiB, used=0.00
root@gra-dfs:/data/tmp#
root@gra-dfs:/home# mount | grep /data
/dev/sda3 on /data type btrfs (rw,noatime,space_cache)
root@gra-dfs:/home#
The setup is supposed to be "RAID-0 like" but with different size drives
within the volume, I created the BTRFS filesystem using the following
command based on the WiKi[1]
mkfs.btrfs -d single /dev/sda3 /dev/sdb /dev/sdc -f
Once setup, I transferred roughly 3.1TB of data and noticed the write
speed was limited to 200MB/s. This is the same write speed that I would
see across a single device. I used dd with oflag=direct and a block size
of 1M and a count of 1024 from /dev/zero. Both showed the same speeds.
So my question is, should I have setup the BTRFS filesystem with -d
raid0? Would this have worked with multiple devices with different sizes?
[1]:
https://btrfs.wiki.kernel.org/index.php/Using_Btrfs_with_Multiple_Devices
--
Adam Brenner <adam@aeb.io>
next reply other threads:[~2014-04-20 18:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-20 17:27 Adam Brenner [this message]
2014-04-20 20:54 ` Slow Write Performance w/ No Cache Enabled and Different Size Drives Chris Murphy
2014-04-20 21:04 ` Chris Murphy
2014-04-21 4:56 ` Adam Brenner
2014-04-21 5:32 ` Chris Murphy
2014-04-21 21:09 ` Duncan
2014-04-22 17:42 ` Chris Murphy
2014-04-22 17:56 ` Hugo Mills
2014-04-22 18:41 ` Chris Murphy
2014-04-23 3:18 ` Duncan
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=53540367.4050707@aeb.io \
--to=adam@aeb.io \
--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.