Re: RAID56 - 6 parity raid

On 05/03/2018 02:47 PM, Alberto Bursi wrote: > > > On 01/05/2018 23:57, Gandalf Corvotempesta wrote: >> Hi to all >> I've found some patches from Andrea Mazzoleni that adds support up to 6 >> parity raid. >> Why these are wasn't merged ? >> With modern disk size, having something greater than 2

Re: RAID56 - 6 parity raid

On 05/03/2018 01:26 PM, Austin S. Hemmelgarn wrote: >> My intention was to highlight that the parity-checksum is not related to the >> reliability and safety of raid5/6. > It may not be related to the safety, but it is arguably indirectly related to > the reliability, dependent on your

Re: RAID56 - 6 parity raid

On 01/05/2018 23:57, Gandalf Corvotempesta wrote: > Hi to all > I've found some patches from Andrea Mazzoleni that adds support up to 6 > parity raid. > Why these are wasn't merged ? > With modern disk size, having something greater than 2 parity, would be > great. > -- > To unsubscribe from

Re: RAID56 - 6 parity raid

On 2018-05-03 04:11, Andrei Borzenkov wrote: On Wed, May 2, 2018 at 10:29 PM, Austin S. Hemmelgarn wrote: ... Assume you have a BTRFS raid5 volume consisting of 6 8TB disks (which gives you 40TB of usable space). You're storing roughly 20TB of data on it, using a 16kB

Re: RAID56 - 6 parity raid

On 2018-05-02 16:40, Goffredo Baroncelli wrote: On 05/02/2018 09:29 PM, Austin S. Hemmelgarn wrote: On 2018-05-02 13:25, Goffredo Baroncelli wrote: On 05/02/2018 06:55 PM, waxhead wrote: So again, which problem would solve having the parity checksummed ? On the best of my knowledge nothing.

Re: RAID56 - 6 parity raid

On Wed, May 2, 2018 at 10:29 PM, Austin S. Hemmelgarn wrote: ... > > Assume you have a BTRFS raid5 volume consisting of 6 8TB disks (which gives > you 40TB of usable space). You're storing roughly 20TB of data on it, using > a 16kB block size, and it sees about 1GB of

Re: RAID56 - 6 parity raid

Goffredo Baroncelli posted on Wed, 02 May 2018 22:40:27 +0200 as excerpted: > Anyway, my "rant" started when Ducan put near the missing of parity > checksum and the write hole. The first might be a performance problem. > Instead the write hole could lead to a loosing data. My intention was to >

Re: RAID56 - 6 parity raid

Gandalf Corvotempesta posted on Wed, 02 May 2018 19:25:41 + as excerpted: > On 05/02/2018 03:47 AM, Duncan wrote: >> Meanwhile, have you looked at zfs? Perhaps they have something like >> that? > > Yes, i've looked at ZFS and I'm using it on some servers but I don't > like it too much for

Re: RAID56 - 6 parity raid

On 05/02/2018 11:20 PM, waxhead wrote: > > [...] > > Ok, before attempting and answer I have to admit that I do not know enough > about how RAID56 is laid out on disk in BTRFS terms. Is data checksummed pr. > stripe or pr. disk? Is parity calculated on the data only or is it calculated > on

Re: RAID56 - 6 parity raid

Andrei Borzenkov wrote: 02.05.2018 21:17, waxhead пишет: Goffredo Baroncelli wrote: On 05/02/2018 06:55 PM, waxhead wrote: So again, which problem would solve having the parity checksummed ? On the best of my knowledge nothing. In any case the data is checksummed so it is impossible to

Re: RAID56 - 6 parity raid

On 05/02/2018 09:29 PM, Austin S. Hemmelgarn wrote: > On 2018-05-02 13:25, Goffredo Baroncelli wrote: >> On 05/02/2018 06:55 PM, waxhead wrote: So again, which problem would solve having the parity checksummed ? On the best of my knowledge nothing. In any case the data is

Re: RAID56 - 6 parity raid

On 2018-05-02 13:25, Goffredo Baroncelli wrote: On 05/02/2018 06:55 PM, waxhead wrote: So again, which problem would solve having the parity checksummed ? On the best of my knowledge nothing. In any case the data is checksummed so it is impossible to return corrupted data (modulo bug :-) ).

Re: RAID56 - 6 parity raid

On 05/02/2018 03:47 AM, Duncan wrote: > Meanwhile, have you looked at zfs? Perhaps they have something like that? Yes, i've looked at ZFS and I'm using it on some servers but I don't like it too much for multiple reasons, in example: 1) is not officially in kernel, we have to build a module

Re: RAID56 - 6 parity raid

On 05/02/2018 08:17 PM, waxhead wrote: > Goffredo Baroncelli wrote: >> On 05/02/2018 06:55 PM, waxhead wrote: So again, which problem would solve having the parity checksummed ? On the best of my knowledge nothing. In any case the data is checksummed so it is impossible to

Re: RAID56 - 6 parity raid

Goffredo Baroncelli wrote: On 05/02/2018 06:55 PM, waxhead wrote: So again, which problem would solve having the parity checksummed ? On the best of my knowledge nothing. In any case the data is checksummed so it is impossible to return corrupted data (modulo bug :-) ). I am not a BTRFS

Re: RAID56 - 6 parity raid

On 05/02/2018 06:55 PM, waxhead wrote: >> >> So again, which problem would solve having the parity checksummed ? On the >> best of my knowledge nothing. In any case the data is checksummed so it is >> impossible to return corrupted data (modulo bug :-) ). >> > I am not a BTRFS dev , but this

Re: RAID56 - 6 parity raid

On 2018-05-02 12:55, waxhead wrote: Goffredo Baroncelli wrote: Hi On 05/02/2018 03:47 AM, Duncan wrote: Gandalf Corvotempesta posted on Tue, 01 May 2018 21:57:59 + as excerpted: Hi to all I've found some patches from Andrea Mazzoleni that adds support up to 6 parity raid. Why these are

Re: RAID56 - 6 parity raid

Goffredo Baroncelli wrote: Hi On 05/02/2018 03:47 AM, Duncan wrote: Gandalf Corvotempesta posted on Tue, 01 May 2018 21:57:59 + as excerpted: Hi to all I've found some patches from Andrea Mazzoleni that adds support up to 6 parity raid. Why these are wasn't merged ? With modern disk size,

Re: RAID56 - 6 parity raid

Hi On 05/02/2018 03:47 AM, Duncan wrote: > Gandalf Corvotempesta posted on Tue, 01 May 2018 21:57:59 + as > excerpted: > >> Hi to all I've found some patches from Andrea Mazzoleni that adds >> support up to 6 parity raid. >> Why these are wasn't merged ? >> With modern disk size, having

Re: RAID56 - 6 parity raid

Gandalf Corvotempesta posted on Tue, 01 May 2018 21:57:59 + as excerpted: > Hi to all I've found some patches from Andrea Mazzoleni that adds > support up to 6 parity raid. > Why these are wasn't merged ? > With modern disk size, having something greater than 2 parity, would be > great. 1)

RAID56 - 6 parity raid

Hi to all I've found some patches from Andrea Mazzoleni that adds support up to 6 parity raid. Why these are wasn't merged ? With modern disk size, having something greater than 2 parity, would be great. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a