From: Goffredo Baroncelli <kreijack@gmail.com>
To: Hugo Mills <hugo@carfax.org.uk>, Gabriel <g2p.code@gmail.com>,
linux-btrfs@vger.kernel.org
Subject: Re: [PATCH][BTRFS-PROGS] Enhance btrfs fi df
Date: Sat, 03 Nov 2012 13:28:12 +0100 [thread overview]
Message-ID: <50950DDC.8060402@gmail.com> (raw)
In-Reply-To: <20121102234419.GD28864@carfax.org.uk>
On 11/03/2012 12:44 AM, Hugo Mills wrote:
> 1 MiB stored in RAID-5 across 3 devices takes up 1.5 MiB -- multiplier ×1.5
> (1 MiB over 2 devices is 512 KiB, plus an additional 512 KiB for parity)
> 1 MiB stored in RAID-5 across 6 devices takes up 1.2 MiB -- multipler ×1.2
> (1 MiB over 5 devices is 204.8 KiB, plus an additional 204.8 KiB for parity)
>
> With the (initial) proposed implementation of RAID-5, the
> stripe-width (i.e. the number of devices used for any given chunk
> allocation) will be *as many as can be allocated*. Chris confirmed
> this today on IRC. So if I have a disk array of 2T, 2T, 2T, 1T, 1T,
> 1T, then the first 1T of allocation will stripe across 6 devices,
Interesting.
Let me simulate a possible output
> ./btrfs filesystem disk-usage -t /
Data Metadata Metadata System System
RAID5 Single DUP Single DUP Unallocated
/dev/dm-0 1.50TB 8.00MB - 4.00MB 16.00MB 500.00MB
/dev/dm-1 1.50TB - - 4.00MB 16.00MB 500.00MB
/dev/dm-2 1.50TB - - 4.00MB - 500.00MB
/dev/dm-3 1.00TB - 2x 100.00MB 4.00MB - 300.00MB
/dev/dm-4 1.00TB - 2x 100.00MB 4.00MB - 300.00MB
======= ======== =========== ====== ======= ===========
Total 5.00TB 8.00MB 200.00MB 4.00MB 8.00MB 2.10TB
Used 10.65GB 0.00 50.00MB 0.00 4.00KB
Would be it clear ? And what if we move the Total/used below the header ?
> ./btrfs filesystem disk-usage -t /
Data Metadata Metadata System System
RAID5 Single DUP Single DUP Unallocated
Total 5.00TB 8.00MB 200.00MB 4.00MB 8.00MB 2.10TB
Used 10.65GB 0.00 50.00MB 0.00 4.00KB
======= ======== =========== ====== ======= ===========
/dev/dm-0 1.50TB 8.00MB - 4.00MB 16.00MB 500.00MB
/dev/dm-1 1.50TB - - 4.00MB 16.00MB 500.00MB
/dev/dm-2 1.50TB - - 4.00MB - 500.00MB
/dev/dm-3 1.00TB - 2x 100.00MB 4.00MB - 300.00MB
/dev/dm-4 1.00TB - 2x 100.00MB 4.00MB - 300.00MB
GB
P.S:
The raid5 is composed by (4+1) x 1T and (2+1) x 0.5TB, supposing the
disks as 2x 1.5TB and 3x2Tb.
--
gpg @keyserver.linux.it: Goffredo Baroncelli (kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
next prev parent reply other threads:[~2012-11-03 12:27 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-02 10:15 [PATCH][BTRFS-PROGS] Enhance btrfs fi df Goffredo Baroncelli
2012-11-02 10:15 ` [PATCH 1/8] Enhance the command btrfs filesystem df Goffredo Baroncelli
2012-11-02 10:15 ` [PATCH 2/8] Create the man page entry for the command btrfs fi df Goffredo Baroncelli
2012-11-02 10:15 ` [PATCH 3/8] Move open_file_or_dir() in utils.c Goffredo Baroncelli
2012-11-02 10:15 ` [PATCH 4/8] Move scrub_fs_info() and scrub_dev_info() " Goffredo Baroncelli
2012-11-02 10:15 ` [PATCH 5/8] Add command btrfs filesystem disk-usage Goffredo Baroncelli
2012-11-02 10:15 ` [PATCH 6/8] Create entry in man page for " Goffredo Baroncelli
2012-11-02 10:15 ` [PATCH 7/8] Add btrfs device disk-usage command Goffredo Baroncelli
2012-11-02 10:15 ` [PATCH 8/8] Create a new entry in btrfs man page for btrfs device disk-usage Goffredo Baroncelli
2012-11-02 11:18 ` [PATCH][BTRFS-PROGS] Enhance btrfs fi df Martin Steigerwald
2012-11-02 12:02 ` Goffredo Baroncelli
2012-11-02 19:05 ` Gabriel
2012-11-02 19:31 ` Goffredo Baroncelli
2012-11-02 20:40 ` Gabriel
2012-11-02 21:46 ` Michael Kjörling
2012-11-02 23:34 ` Gabriel
2012-11-02 22:06 ` Hugo Mills
2012-11-02 23:23 ` Gabriel
2012-11-02 23:44 ` Hugo Mills
2012-11-03 0:14 ` Gabriel
2012-11-03 12:28 ` Goffredo Baroncelli [this message]
2012-11-03 12:35 ` Goffredo Baroncelli
2012-11-03 22:04 ` cwillu
2012-11-03 12:11 ` Goffredo Baroncelli
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