[Solved] Cache upgrade recommendation

[FreeMan]

I currently have a single 240GB SSD as the cache drive in my server. I just picked up 2 more 240GB SSDs. 

 

What are the pros and cons of:

1. Using 2 of the SSDs in a RAID 1 array as a cache drive and assign my appdata share to be cache Preferred, then use the other SSD mounted via UD for some other purposes
2. Continuing with 1 SSD as a cache and mounting 2 SSDs via UD and putting my appdata share on the UD mounted partitions
3. Continuing with 1 SSD as cache and adding the 2 SSDs to the array and adjusting the appdata share to use these drives only and allow appdata to live in the protected array (I'd also set all the other shares to ignore these 2 drives).
4. Is there a reasonable way of using all 3 SSDs as cache so that most or all the space is available
5. Other suggestions.

Edited December 28, 2019 by FreeMan

[itimpi]

I would not recommend going with 3) as this is not an officially supported configuration; depending on the model of SSD might not play well with parity; and performance (writing) will be limited by the speed of the parity drive.

 

regarding the other options how important is to you to have data on the SSDs protected?   This might help decide between the other options.

[FreeMan]

I've run since v5.0 with a single cache drive, and I currently use CA backup to backup weekly. My thinking was to add an SSD to make a RAID array of out them. But then I ended up with 3 and was wondering if there might be a better /different option.

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[trurl]

btrfs will allow raid1 with 3 disks, which will give you more capacity than just a simple mirror of 2 disks.

 

See here:

 

https://carfax.org.uk/btrfs-usage/

[FreeMan]

Sweet! I'll check that out

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[trurl]

And raid0 will give total capacity without mirror.

 

Also see here:

 

https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=480421

 

[FreeMan]

And raid0 will give total capacity without mirror.
 
Also see here:
 
https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=480421
 

Well, the goal was to have some sort of redundancy. Looks like a 3 drive RAID 1 array is the way to go.

I presume I will need to move all the data of the current drive to set that up. or can I simply add the disks and magic will happen?

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[trurl]

2 minutes ago, FreeMan said:

can I simply add the disks and magic will happen?

Take a look at the other posts in the FAQ under the Cache Drive/Pool section:

 

https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=554741

 

[Melocco]

I have two drives (256gb) in my cache setup in a raid 0 (stripped). I am wanting to add two (256gb all same manufacture) more and possibly change to a raid 10.  I seen a post showing that I need to disable my docker, reinstall all the dockers after and alot more steps to upgrade. If I just go with adding the drives as is, can I just stop the array and add the drives one at a time or both at once, or basically almost start over with all the dockers etc.? Another option would be replace both drives with 2 512gb drives and use it instead.

 

Basically what I am asking is what is the best way to proceed? I know I should have went with larger drives in the beginning, but I was a Nube then. I'm just trying to figure out mt best option forward..   Thanks in advance...   

Edited December 27, 2019 by Melocco

[JorgeB]

3 hours ago, Melocco said:

If I just go with adding the drives as is, can I just stop the array and add the drives one at a time or both at once

You can add one or both new devices to the pool, then convert to raid10 and do it all with the pool online, not need to stop anything, though always good practice to backup anything important before beginning just in case something goes wrong.

[FreeMan]

On 12/26/2019 at 10:50 PM, trurl said:

Take a look at the other posts in the FAQ under the Cache Drive/Pool section:

according to this

it looks like "magic happens" is the correct option!

 

thanks for all the help!

[FreeMan]

Installed the two drives, brought the server up, stopped the array, expanded the cache slots, added the drives, started the array, and magic!

 

Once again, Unraid blows me away with its simplicity and It Just Works™-ness

[Melocco]

Thanks johnnie.  I was hoping it was as simple as that..   I just wish raid 6 or 5 was more reliable..  Ether way, I got it working. Thanks...