Cyril B.
2012-Jul-25 13:26 UTC
mkfs devices ordering relevant with devices of different sizes?
Hello,
When creating a filesystem with devices of different sizes, the resulting
filesystem total size depends on the device order specified to mkfs. When
the smaller device is specified first, the second (larger) device is seen as
the same size as the first. This doesn''t occur when the order is
reversed.
It''s confusing. Is this expected? I''m using the latest
btrfs-progs and Linux
3.5.
# ./mkfs.btrfs /dev/sda4 /dev/sdc
WARNING! - Btrfs Btrfs v0.19 IS EXPERIMENTAL
WARNING! - see http://btrfs.wiki.kernel.org before using
adding device /dev/sdc id 2
fs created label (null) on /dev/sda4
nodesize 4096 leafsize 4096 sectorsize 4096 size 3.97TB
Btrfs Btrfs v0.19
backup6:~/btrfs-progs# ./btrfs fi show /dev/sdc
Label: none uuid: 806b237e-53ed-409e-a7c1-02f101798384
Total devices 2 FS bytes used 28.00KB
devid 2 size 1.98TB used 2.01GB path /dev/sdc
devid 1 size 1.98TB used 2.03GB path /dev/sda4
Btrfs Btrfs v0.19
# ./mkfs.btrfs /dev/sdc /dev/sda4
WARNING! - Btrfs Btrfs v0.19 IS EXPERIMENTAL
WARNING! - see http://btrfs.wiki.kernel.org before using
adding device /dev/sda4 id 2
fs created label (null) on /dev/sdc
nodesize 4096 leafsize 4096 sectorsize 4096 size 4.71TB
Btrfs Btrfs v0.19
backup6:~/btrfs-progs# ./btrfs fi show /dev/sdc
Label: none uuid: 8f99c072-521b-4827-a2be-41de6ab11b4f
Total devices 2 FS bytes used 28.00KB
devid 1 size 2.73TB used 2.03GB path /dev/sdc
devid 2 size 1.98TB used 2.01GB path /dev/sda4
Btrfs Btrfs v0.19
Thanks.
--
Cyril B.
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David Sterba
2012-Jul-26 21:09 UTC
Re: mkfs devices ordering relevant with devices of different sizes?
On Wed, Jul 25, 2012 at 03:26:20PM +0200, Cyril B. wrote:> When creating a filesystem with devices of different sizes, the resulting > filesystem total size depends on the device order specified to mkfs. When > the smaller device is specified first, the second (larger) device is seen as > the same size as the first. This doesn''t occur when the order is reversed. > > It''s confusing. Is this expected? I''m using the latest btrfs-progs and Linux > 3.5.Confusing it is, caused by this commit Author: Josef Bacik <josef@redhat.com> AuthorDate: Wed Mar 28 14:20:52 2012 -0400 Commit: Chris Mason <chris.mason@fusionio.com> CommitDate: Tue Jul 3 16:27:46 2012 -0400 btrfs-progs: enforce block count on all devices in mkfs I had a test that creates a 7gig raid1 device but it was ending up wonky because the second device that gets added is the full size of the disk instead of the limited size. So enforce the limited size on all disks passed in at mkfs time, otherwise our threshold calculations end up wonky when doing chunk allocations. Thanks, --- david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Josef Bacik
2012-Jul-27 12:05 UTC
Re: mkfs devices ordering relevant with devices of different sizes?
On Thu, Jul 26, 2012 at 03:09:59PM -0600, David Sterba wrote:> On Wed, Jul 25, 2012 at 03:26:20PM +0200, Cyril B. wrote: > > When creating a filesystem with devices of different sizes, the resulting > > filesystem total size depends on the device order specified to mkfs. When > > the smaller device is specified first, the second (larger) device is seen as > > the same size as the first. This doesn''t occur when the order is reversed. > > > > It''s confusing. Is this expected? I''m using the latest btrfs-progs and Linux > > 3.5. > > Confusing it is, caused by this commit > > Author: Josef Bacik <josef@redhat.com> > AuthorDate: Wed Mar 28 14:20:52 2012 -0400 > Commit: Chris Mason <chris.mason@fusionio.com> > CommitDate: Tue Jul 3 16:27:46 2012 -0400 > > btrfs-progs: enforce block count on all devices in mkfs > > I had a test that creates a 7gig raid1 device but it was ending up wonky > because the second device that gets added is the full size of the disk > instead of the limited size. So enforce the limited size on all disks > passed in at mkfs time, otherwise our threshold calculations end up wonky > when doing chunk allocations. Thanks,Ooops, that''s definitely not what I intended, I will fix that up right away, sorry about that. Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html