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

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

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. The idea and the code are similar to the write-through mode