Adding a new drive to a RAID 5 group

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RZR1988
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Adding a new drive to a RAID 5 group

Post by RZR1988 » Sat Sep 14, 2019 2:24 am

I have done some reading, and while I think I have the answer, I would like confirmation from someone who has done it.

I currently have 3x8TB drives in a RAID 5 group - if I add another, do the other drives need to be formatted? If they do, is there a way to increase the capacity of the storage pool without losing anything?

P3R
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Re: Adding a new drive to a RAID 5 group

Post by P3R » Sat Sep 14, 2019 3:48 am

RZR1988 wrote:
Sat Sep 14, 2019 2:24 am
I currently have 3x8TB drives in a RAID 5 group - if I add another, do the other drives need to be formatted? If they do, is there a way to increase the capacity of the storage pool without losing anything?
If they need formatting, there would be no way to increase the number of disks in the RAID group without deleting a pool and/or anything else dependent on it.

To know for sure I would recommend that you read under the heading Adding Hard Disk Drives in the documentation section about RAID Groups. I don't know where you've been reading but this would be the place to find correct information.

As anything can go wrong at any time a backup copy of all data on a separate system is always a requirement for any data that have any value, not only when considering advanced RAID management like you ask about here.
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!

RZR1988
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Re: Adding a new drive to a RAID 5 group

Post by RZR1988 » Sat Sep 14, 2019 4:40 am

Thank you for that link, it was superior to what Google turned up. I'm not concerned about the data; its not critical and I have backups, but just really lazy to copy everything back onto the NAS again (couple of TB will take a while).

After reading your link, I think I misinterpreted the information first time around:

Adding Hard Disk Drives

With this function, new drive members can be added to a RAID group. This option is supported for RAID 5 and RAID 6 drive configurations.
Follow these steps to add the hard disk drive(s) to a RAID group:
1. Go to "Storage Manager" > "STORAGE" > "Storage Space".
2. Double click a storage pool to bring up the Storage Pool Management page.
3. Select a RAID group and click "Manage" > "Add Hard Drive".
4. Select hard disk drive(s) from the list to add to the chosen RAID group and click "Apply".
5. Please note that all data on the selected hard drive(s) will be erased. Click "Yes" if you are certain about this.
6. The chosen hard disk drive(s) are added to the selected RAID group.

I take point 5 now to mean that any data on a drive being added into the RAID group will be wiped - which is fine since I will be adding a brand new drive with nothing on it. My interpretation is that the existing RAID group/storage pool will remain untouched, with whatever data is present.

P3R
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Re: Adding a new drive to a RAID 5 group

Post by P3R » Sat Sep 14, 2019 6:49 am

RZR1988 wrote:
Sat Sep 14, 2019 4:40 am
Thank you for that link, it was superior to what Google turned up.
Don't google by default. Instead go to the source when it's obvious, as in this case. After that, google for confirmation if necessary.
I take point 5 now to mean that any data on a drive being added into the RAID group will be wiped...
Correct.
My interpretation is that the existing RAID group/storage pool will remain untouched, with whatever data is present.
Correct and the RAID group will be expanded across all disks (including the new member of the RAID), which will allow you to increase the size of whatever usage of the storage that you have of the pool.
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!

dolbyman
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Re: Adding a new drive to a RAID 5 group

Post by dolbyman » Sat Sep 14, 2019 7:22 am

lots of people have issues with the wording in rhe manual

viewtopic.php?f=25&t=150336&p=725881#p725881

RZR1988
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Re: Adding a new drive to a RAID 5 group

Post by RZR1988 » Sat Sep 14, 2019 3:51 pm

So it seems... thank you though gentlemen, this is exactly what I was hoping for. Really appreciate the assistance and clarity!

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