Hot Spare & SHR

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thegraingers
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Hot Spare & SHR

Unread post by thegraingers » Mon Feb 27, 2017 11:07 am

I have configured my DS416PLAY with one of its drives as a hot spare and a single volume on the other three drives, which is configured as a Synology Hybrid RAID. (All 4 drives are the same size).

The help documentation says the following about hot spares

"The RAID type of the volume/Disk Group/iSCSI LUN must be one with data protection (i.e. RAID 1, RAID 5, RAID 6, RAID 10)."

I can't find confirmation that the hot spare will work on my NAS.
DaveG
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horizonbrave
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Re: Hot Spare & SHR

Unread post by horizonbrave » Sun Sep 16, 2018 10:36 am

Today I asked myself the very same question.
Please anyone? Cheers :)

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sciurius
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Re: Hot Spare & SHR

Unread post by sciurius » Sun Sep 16, 2018 9:36 pm

If you open Storage Manager and inspect Storage Pool, you can see the hot spare in the overview, table "Available hot spare disks".
DS418 / DSM 6.2-23739 Update 2 / 2 x WD40EFRX-68WT0N0 (SHR) / MailServer / MailStation / ownCloud / Transmission / ResilioSync / Syncthing / spotweb / LMS+Spotify
DS413 / DSM 6.2-23739 Update 2 / 2 x ST3000DM001-1CH166 (SHR) / Testing

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Re: Hot Spare & SHR

Unread post by horizonbrave » Mon Sep 17, 2018 1:31 am

Is it a Yes? Sorry I just ordered my Synology and can't check it yet, and I was trying to decide between RAID 6 and SHR 2.
Cheers

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Re: Hot Spare & SHR

Unread post by telos » Mon Sep 17, 2018 3:47 am

Why do you want a "hot spare"?
https://blog.open-e.com/why-a-hot-spare ... -bad-idea/

... and for RAID6??? Please why.

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Re: Hot Spare & SHR

Unread post by horizonbrave » Mon Sep 17, 2018 4:44 am

I was actually reading that article yesterday... I'm just gathering informations here :)
I think if backups are implemented correctly hot-spares are not such a bad idea (but I'm a total noob).
Thanks!

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sciurius
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Re: Hot Spare & SHR

Unread post by sciurius » Mon Sep 17, 2018 7:33 am

It makes me wonder what would be the hardest strain on the disks: parity rebuild, complete backup, or disk clone?
DS418 / DSM 6.2-23739 Update 2 / 2 x WD40EFRX-68WT0N0 (SHR) / MailServer / MailStation / ownCloud / Transmission / ResilioSync / Syncthing / spotweb / LMS+Spotify
DS413 / DSM 6.2-23739 Update 2 / 2 x ST3000DM001-1CH166 (SHR) / Testing

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Re: Hot Spare & SHR

Unread post by Squozen » Mon Sep 17, 2018 1:50 pm

telos wrote:
Mon Sep 17, 2018 3:47 am
Why do you want a "hot spare"?
https://blog.open-e.com/why-a-hot-spare ... -bad-idea/

... and for RAID6??? Please why.
I think that article is nonsense for the enterprise. The backup should already be done as a matter of course, not at the last minute with a degraded RAID array. And the comments from other storage admins agree with me.

Hot spares are tremendous in the enterprise as disk scrubs happen on a weekly (or shorter) interval and drives exhibiting the slightest hint of errors are dropped from the array with great prejudice. I've never had an array fail during a hot spare rebuild because of this.

Consumer NASs allow complete garbage to stay in the array so the chance of a failure during a rebuild is much more likely. But even in this situation I could see somebody preferring to know that they have bad drives sooner rather than later so they can get on with restoring from backup onto a fresh array.

That being said, I only run with SHR2 at home and no hot spare. When a drive fails I shut the NAS down until I obtain a replacement drive. I guess that is ghetto hot-spare. :)

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Re: Hot Spare & SHR

Unread post by telos » Mon Sep 17, 2018 3:52 pm

Squozen wrote:
Mon Sep 17, 2018 1:50 pm
That being said, I only run with SHR2 at home and no hot spare. When a drive fails I shut the NAS down until I obtain a replacement drive. I guess that is ghetto hot-spare. :)
This too is my MO. I would never want a hot spare to auto-rebuild the array. Before I would undertake a rebuild, I want to confirm that my backups are current as there is a moderately high risk of disk failure during a rebuild. I'm content to assure backup integrity using a degraded array. Once that is done, then I rebuild.

And yes, enterprise systems are a different beast and methodology, and the assurance of up-to-date backups are presumed.

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