Two Raid5 or one Raid6

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Don
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Re: Two Raid5 or one Raid6

Post by Don »

Spider99 wrote:Yes i am a naughty boy :lol:
Off with his head. :twisted:

Whatever time it takes to rebuild and restore is time that your apps/data are unavailable. Just something else to consider.
Use the forum search feature before posting.

Use RAID and external backups. RAID will protect you from disk failure, keep your system running, and data accessible while the disk is replaced, and the RAID rebuilt. Backups will allow you to recover data that is lost or corrupted, or from system failure. One does not replace the other.

NAS: TVS-882BR | F/W: 5.0.1.2346 | 40GB | 2 x 1TB M.2 SATA RAID 1 (System/VMs) | 3 x 1TB M.2 NMVe QM2-4P-384A RAID 5 (cache) | 5 x 14TB Exos HDD RAID 6 (Data) | 1 x Blu-ray
NAS: TVS-h674 | F/W: 5.0.1.2376 | 16GB | 3 x 18TB RAID 5
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P3R
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Re: Two Raid5 or one Raid6

Post by P3R »

MrVideo wrote:So, if the first two drives were to go bad you lose that RAID5, but not the other. If the same to drives go bad in the RAID6, you lose all the data.
Think again! The RAID 6 and it's data is still perfectly available with two failed disks!

An 8 disk RAID 6 is safer, easier to manage and have about twice the performance of 2*4 disk RAID 5s. The only reason for having two RAID 5 arrays is if different disk sizes need to be used.
RAID have never ever been a replacement for backups. Without backups on a different system (preferably placed at another site), you will eventually lose data!

A non-RAID configuration (including RAID 0, which isn't really RAID) with a backup on a separate media protects your data far better than any RAID-volume without backup.

All data storage consists of both the primary storage and the backups. It's your money and your data, spend the storage budget wisely or pay with your data!
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Spider99
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Re: Two Raid5 or one Raid6

Post by Spider99 »

have about twice the performance of 2*4 disk RAID 5s
Really? What do you base that statement on?
Tim

TS-853A(16GB): - 4.3.4.0483 - Static volume - Raid5 - 8 x 4TB HGST Deskstar NAS
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P3R
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Re: Two Raid5 or one Raid6

Post by P3R »

Spider99 wrote:Really? What do you base that statement on?
Spreading data over twice the number of disks gives about twice the performance as only half the amount the amount of data needs to be read/written from/to each disk. I should have added that it only applies to writing, given a fast CPU. Here's some testing to confirm it.
RAID have never ever been a replacement for backups. Without backups on a different system (preferably placed at another site), you will eventually lose data!

A non-RAID configuration (including RAID 0, which isn't really RAID) with a backup on a separate media protects your data far better than any RAID-volume without backup.

All data storage consists of both the primary storage and the backups. It's your money and your data, spend the storage budget wisely or pay with your data!
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MrVideo
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Re: Two Raid5 or one Raid6

Post by MrVideo »

P3R wrote:
MrVideo wrote:So, if the first two drives were to go bad you lose that RAID5, but not the other. If the same to drives go bad in the RAID6, you lose all the data.
Think again! The RAID 6 and it's data is still perfectly available with two failed disks!
Oops! Brain/keyboard disconnect.
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WD60EFRX-68L0BN1(x1)/68MYMN1(x7) Red HDDs -- RAID6: 8x6TB -- Cold spare: 1x6TB
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===============================
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===============================
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