Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On 08/02/2017 08:47 PM, Chris Mason wrote: >> I agree, MD pretty much needs a separate device simply because they can't >> allocate arbitrary space on the other array members.  BTRFS can do that >> though, and I would actually think that that would be _easier_ to implement >> than having a

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On 08/23/2017 05:28 PM, Chris Murphy wrote: > - dynamically sized stripes, so that writes can always be full stripe > writes, no overwrites, and atomic Think about also that a block could be deallocated (i.e. canceling a file of 4kb). This leads to have some holes that you cannot fill without a

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On 2017-08-23 11:28, Chris Murphy wrote: On Wed, Aug 2, 2017 at 2:27 PM, Liu Bo wrote: On Wed, Aug 02, 2017 at 10:41:30PM +0200, Goffredo Baroncelli wrote: What I want to understand, is if it is possible to log only the "partial stripe" RMW cycle. I think your

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On Wed, Aug 2, 2017 at 2:27 PM, Liu Bo wrote: > On Wed, Aug 02, 2017 at 10:41:30PM +0200, Goffredo Baroncelli wrote: >> What I want to understand, is if it is possible to log only the "partial >> stripe" RMW cycle. >> > > I think your point is valid if all data is written

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On 2017-08-03 06:02, Duncan wrote: > Liu Bo posted on Wed, 02 Aug 2017 14:27:21 -0600 as excerpted: > > It is correct reading this as: all data is written two times ? > > If as is being discussed the log is mirrored by default that'd be three > times... And for raid6 you need to do it 4

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

Liu Bo posted on Wed, 02 Aug 2017 14:27:21 -0600 as excerpted: >> >> It is correct reading this as: all data is written two times ? If as is being discussed the log is mirrored by default that'd be three times... Parity-raid is slow and of course normally has the infamous write hole this

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On Wed, Aug 02, 2017 at 10:41:30PM +0200, Goffredo Baroncelli wrote: > Hi Liu, > > thanks for your reply, below my comments > On 2017-08-02 19:57, Liu Bo wrote: > > On Wed, Aug 02, 2017 at 12:14:27AM +0200, Goffredo Baroncelli wrote: > >> On 2017-08-01 19:24, Liu Bo wrote: > >>> On Tue, Aug 01,

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

Hi Liu, thanks for your reply, below my comments On 2017-08-02 19:57, Liu Bo wrote: > On Wed, Aug 02, 2017 at 12:14:27AM +0200, Goffredo Baroncelli wrote: >> On 2017-08-01 19:24, Liu Bo wrote: >>> On Tue, Aug 01, 2017 at 07:42:14PM +0200, Goffredo Baroncelli wrote: Hi Liu, On

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On Wed, Aug 02, 2017 at 12:14:27AM +0200, Goffredo Baroncelli wrote: > On 2017-08-01 19:24, Liu Bo wrote: > > On Tue, Aug 01, 2017 at 07:42:14PM +0200, Goffredo Baroncelli wrote: > >> Hi Liu, > >> > >> On 2017-08-01 18:14, Liu Bo wrote: > >>> This aims to fix write hole issue on btrfs raid5/6

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On 08/01/2017 01:39 PM, Austin S. Hemmelgarn wrote: On 2017-08-01 13:25, Roman Mamedov wrote: On Tue, 1 Aug 2017 10:14:23 -0600 Liu Bo wrote: This aims to fix write hole issue on btrfs raid5/6 setup by adding a separate disk as a journal (aka raid5/6 log), so that

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On 2017-08-01 23:00, Christoph Anton Mitterer wrote: > Hi. > > Stupid question: > Would the write hole be closed already, if parity was checksummed? No. The write hole problem is due to a combination of two things: a) misalignment between parity and data (i.e. unclean shutdown) b) loosing of a

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On 2017-08-01 19:24, Liu Bo wrote: > On Tue, Aug 01, 2017 at 07:42:14PM +0200, Goffredo Baroncelli wrote: >> Hi Liu, >> >> On 2017-08-01 18:14, Liu Bo wrote: >>> This aims to fix write hole issue on btrfs raid5/6 setup by adding a >>> separate disk as a journal (aka raid5/6 log), so that after

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

Hi. Stupid question: Would the write hole be closed already, if parity was checksummed? Cheers, Chris. smime.p7s Description: S/MIME cryptographic signature

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On Tue, Aug 01, 2017 at 07:42:14PM +0200, Goffredo Baroncelli wrote: > Hi Liu, > > On 2017-08-01 18:14, Liu Bo wrote: > > This aims to fix write hole issue on btrfs raid5/6 setup by adding a > > separate disk as a journal (aka raid5/6 log), so that after unclean > > shutdown we can make sure data

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On Tue, Aug 01, 2017 at 10:56:39AM -0600, Liu Bo wrote: > On Tue, Aug 01, 2017 at 05:28:57PM +, Hugo Mills wrote: > >Hi, > > > >Great to see something addressing the write hole at last. > > > > On Tue, Aug 01, 2017 at 10:14:23AM -0600, Liu Bo wrote: > > > This aims to fix write hole

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On Tue, Aug 01, 2017 at 01:39:59PM -0400, Austin S. Hemmelgarn wrote: > On 2017-08-01 13:25, Roman Mamedov wrote: > > On Tue, 1 Aug 2017 10:14:23 -0600 > > Liu Bo wrote: > > > > > This aims to fix write hole issue on btrfs raid5/6 setup by adding a > > > separate disk as a

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On Tue, Aug 01, 2017 at 10:25:47PM +0500, Roman Mamedov wrote: > On Tue, 1 Aug 2017 10:14:23 -0600 > Liu Bo wrote: > > > This aims to fix write hole issue on btrfs raid5/6 setup by adding a > > separate disk as a journal (aka raid5/6 log), so that after unclean > >

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On Tue, Aug 01, 2017 at 05:28:57PM +, Hugo Mills wrote: >Hi, > >Great to see something addressing the write hole at last. > > On Tue, Aug 01, 2017 at 10:14:23AM -0600, Liu Bo wrote: > > This aims to fix write hole issue on btrfs raid5/6 setup by adding a > > separate disk as a

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

Hi Liu, On 2017-08-01 18:14, Liu Bo wrote: > This aims to fix write hole issue on btrfs raid5/6 setup by adding a > separate disk as a journal (aka raid5/6 log), so that after unclean > shutdown we can make sure data and parity are consistent on the raid > array by replaying the journal. > it

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On 2017-08-01 13:25, Roman Mamedov wrote: On Tue, 1 Aug 2017 10:14:23 -0600 Liu Bo wrote: This aims to fix write hole issue on btrfs raid5/6 setup by adding a separate disk as a journal (aka raid5/6 log), so that after unclean shutdown we can make sure data and parity

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

Hi, Great to see something addressing the write hole at last. On Tue, Aug 01, 2017 at 10:14:23AM -0600, Liu Bo wrote: > This aims to fix write hole issue on btrfs raid5/6 setup by adding a > separate disk as a journal (aka raid5/6 log), so that after unclean > shutdown we can make sure

Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes

On Tue, 1 Aug 2017 10:14:23 -0600 Liu Bo wrote: > This aims to fix write hole issue on btrfs raid5/6 setup by adding a > separate disk as a journal (aka raid5/6 log), so that after unclean > shutdown we can make sure data and parity are consistent on the raid > array by