From: Roberto Fastec <roberto.fastec@gmail.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] Documentation about allowing >2 disk failures?
Date: Mon, 10 Jul 2023 10:22:56 +0200 [thread overview]
Message-ID: <0d6ce898-371d-4dba-b07e-09ca5a101752@gmail.com> (raw)
In-Reply-To: <CAHLUNMxrWdjgsL-mT=sWxvoAEHUP=4dqmSXt6+ZppdnwSyykSg@mail.gmail.com>
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Hello Tim
LVM is a sort of layer and it can reside on any substrate
So go for raid 60 and avoid using too many drives for each RAID 6
Ideally I would use maximum 6x drives for each RAID 6 to next be stack on RAID 10 with the others
bear in mind that there is a calculation about guaranteed failure of given RAID rebuild process when you exceed a certain amount of terabytes capacity to rebuild
That is why enterprise storages with lot of terabytes are always subdivided in the needed amount of RAID 5 or RAID 6 blocks to be next stack on RAID 50 or RAID 60
At recuperodatiraidfastec.it we have seen so many cases of failed rebuilds due to leak of calculation before implementation
Kind regards
Roberto Gini
CTO @ https://www
RecuperoDatiRAIDFAsTec.it
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Il giorno 10 lug 2023, 08:47, alle ore 08:47, Tim 'mithro' Ansell <me@mith.ro> ha scritto:
>Hello!
>
>RAID5 survives 1 disk failure and RAID6 survives 2 disk failures. What
>about going beyond 2 disk failures? Does anyone know where I can find
>information on what good options might be?
>
>I was looking at RAID10, but every extra mirror added only increases
>failure tolerance by 1 disk. I am also not seeing any inbuilt support
>in
>LVM for RAID50 or RAID60 but it seems like if I manually build the
>sub-volumes, things should still be fine?
>
>My system has 25 disks and I'd like to tolerate up to ~1/3rd of the
>disks
>failing so I was thinking that a RAID1 with 3 mirrors built out of
>RAID6
>with 8 disks each (and 1 hot spare) would be a potentially good option?
>
>Thank you for your help!
>
>Tim 'mithro' Ansell
>
>
>------------------------------------------------------------------------
>
>_______________________________________________
>linux-lvm mailing list
>linux-lvm@redhat.com
>https://listman.redhat.com/mailman/listinfo/linux-lvm
>read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
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prev parent reply other threads:[~2023-07-11 6:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-10 4:41 [linux-lvm] Documentation about allowing >2 disk failures? Tim 'mithro' Ansell
2023-07-10 8:22 ` Roberto Fastec [this message]
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