Re: Using mount -o bind vs mount -o subvol=vol

2014-05-07 Thread Marc MERLIN
On Mon, May 05, 2014 at 02:12:30AM +, Duncan wrote: Marc MERLIN posted on Sat, 03 May 2014 17:47:32 -0700 as excerpted: Just as an FYI, like (likely) most subscribers, I do prefer Cc on replies. Without that, I'm much less likely to see your message timely, or at all if I'm behind on Email.

Re: Using mount -o bind vs mount -o subvol=vol

2014-05-07 Thread Duncan
Marc MERLIN posted on Wed, 07 May 2014 03:55:51 -0700 as excerpted: subvolumes are also used as units of backup for btrfs send. Hmm, yes. Thanks. I don't use send/receive here so forgot about that. So my vote would be, for example (modified slightly for posting from my own mounts):

Re: Using mount -o bind vs mount -o subvol=vol

2014-05-06 Thread Duncan
Brendan Hide posted on Mon, 05 May 2014 08:55:55 +0200 as excerpted: You are 100% right, though. The scale is very small. By negligible, the penalty is at most a few CPU cycles. When compared to the wait time on a spindle, it really doesn't matter much. The analogy I've used before is that of

Re: Using mount -o bind vs mount -o subvol=vol

2014-05-06 Thread Duncan
Marc MERLIN posted on Sat, 03 May 2014 17:47:32 -0700 as excerpted: Is there any functional difference between mount -o subvol=usr /dev/sda1 /usr and mount /dev/sda1 /mnt/btrfs_pool mount -o bind /mnt/btrfs_pool/usr /usr ? Brendan answered the primary aspect of this well so I won't

Re: Using mount -o bind vs mount -o subvol=vol

2014-05-05 Thread Brendan Hide
On 05/05/14 06:36, Roman Mamedov wrote: On Mon, 05 May 2014 06:13:30 +0200 Brendan Hide bren...@swiftspirit.co.za wrote: 1) There will be a *very* small performance penalty (negligible, really) Oh, really, it's slower to mount the device directly? Not that I really care, but that's

Re: Using mount -o bind vs mount -o subvol=vol

2014-05-05 Thread Chris Mason
On 05/03/2014 08:47 PM, Marc MERLIN wrote: Is there any functional difference between mount -o subvol=usr /dev/sda1 /usr and mount /dev/sda1 /mnt/btrfs_pool mount -o bind /mnt/btrfs_pool/usr /usr The internal implementation of mount -o subvol is a bind mount. The only real difference is

Re: Using mount -o bind vs mount -o subvol=vol

2014-05-04 Thread Brendan Hide
On 2014/05/04 02:47 AM, Marc MERLIN wrote: Is there any functional difference between mount -o subvol=usr /dev/sda1 /usr and mount /dev/sda1 /mnt/btrfs_pool mount -o bind /mnt/btrfs_pool/usr /usr ? Thanks, Marc There are two issues with this. 1) There will be a *very* small performance

Re: Using mount -o bind vs mount -o subvol=vol

2014-05-04 Thread Brendan Hide
On 2014/05/05 02:56 AM, Marc MERLIN wrote: On Sun, May 04, 2014 at 09:07:55AM +0200, Brendan Hide wrote: On 2014/05/04 02:47 AM, Marc MERLIN wrote: Is there any functional difference between mount -o subvol=usr /dev/sda1 /usr and mount /dev/sda1 /mnt/btrfs_pool mount -o bind

Re: Using mount -o bind vs mount -o subvol=vol

2014-05-04 Thread Roman Mamedov
On Mon, 05 May 2014 06:13:30 +0200 Brendan Hide bren...@swiftspirit.co.za wrote: 1) There will be a *very* small performance penalty (negligible, really) Oh, really, it's slower to mount the device directly? Not that I really care, but that's unexpected. Um ... the penalty is if you're

Re: Using mount -o bind vs mount -o subvol=vol

2014-05-04 Thread Marc MERLIN
On Mon, May 05, 2014 at 06:13:30AM +0200, Brendan Hide wrote: Oh, really, it's slower to mount the device directly? Not that I really care, but that's unexpected. Um ... the penalty is if you're mounting indirectly. ;) I'd be willing to believe that more then :) (but indeed, if slowdown

Using mount -o bind vs mount -o subvol=vol

2014-05-03 Thread Marc MERLIN
Is there any functional difference between mount -o subvol=usr /dev/sda1 /usr and mount /dev/sda1 /mnt/btrfs_pool mount -o bind /mnt/btrfs_pool/usr /usr ? Thanks, Marc -- A mouse is a device used to point at the xterm you want to type in - A.S.R. Microsoft is to operating systems