From: Hubert Tonneau <hubert.tonneau@fullpliant.org>
To: Goffredo Baroncelli <kreijack@libero.it>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Avoiding BRTFS RAID5 write hole
Date: Tue, 12 Nov 2019 22:27:04 GMT [thread overview]
Message-ID: <0JG92D511@briare1.fullpliant.org> (raw)
Goffredo Baroncelli wrote:
>
> Instead I would like to investigate the idea of COW-ing the stripe: instead of updating the stripe on place, why not write the new stripe in another place and then update the data extent to point to the new data ? Of course would work only for the data and not for the metadata.
We are saying the same.
What I am suggesting is to write it as RAID1 instead of RAID5, so that if it's changed a lot of times, you pay only once.
The background process would then turn it back to RAID5 at a later point.
Adjusting how aggressively this background process works enables to adjust the extra write cost versus saved disk space compromise.
next reply other threads:[~2019-11-12 21:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 22:27 Hubert Tonneau [this message]
2019-11-13 19:34 ` Avoiding BRTFS RAID5 write hole Goffredo Baroncelli
-- strict thread matches above, loose matches on Subject: below --
2019-11-13 22:29 Hubert Tonneau
2019-11-13 22:51 ` waxhead
2019-11-14 21:25 ` Goffredo Baroncelli
2019-11-15 20:41 ` Hubert Tonneau
2019-11-17 8:53 ` Goffredo Baroncelli
2019-11-17 19:49 ` Hubert Tonneau
2019-11-28 11:37 ` Hubert Tonneau
2019-11-12 15:13 Hubert Tonneau
2019-11-12 18:44 ` Chris Murphy
2019-11-12 19:49 ` Goffredo Baroncelli
2019-11-14 4:25 ` Zygo Blaxell
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