Change SSD Disk 1 to Cache and other setup adjustments

[pavel.b]

Hi guys,

 

I need an advice about my unRAID setup.

 

I have currently

• Parity: WDC_WD40EFRX-68N32N0_WD-WCC7K0AX8TV6 - 4 TB (sdb)
• Disk 1: Samsung_SSD_960_EVO_500GB_S3EUNX0J117017X - 500 GB (nvme0n1)
• Disk 2: WDC_WD40EFRX-68N32N0_WD-WCC7K0XNAZ5S - 4 TB (sdc)

 

The thing about this setup is that I used the 500GB SSD as one of the disks so the parity is now using it.

I saved all the VMs, and Docker images to this drive for better performance (this SSD is m.2 drive which is crazy fast, about 1400 Mb/s).

 

Then I have unused

• 250GB SSD (about 500 Mb/s)
• 3TB general magnetic drive from Western Digital (RED edition), same like other two which I am already using just 3TB instead of 4TB.

 

So now, I need to use all of them and do it right this time

 

• Permanently remove the 500GB SSD from array as the storage drive and use it as cache drive
• Move all data from Disk 1 (500GB SSD) to new cache drive (500GB SSD) = same drive
• Add new 250GB SSD
• Set SSD Pool (I am not sure how will the two different sizes and speeds of this drives play together)
  • I still want to use primarily m.2 500GB SSD for its speed
  • but for network transfer, 250GB SSD is still fine (I will not exceed 110 Mb/s network transfer)
  • does it even make sense to use this drives in the pool?
• Add new 3TB drive
• My main concern is that I need to transfer all VMs and Docker images from current Disk 1 to new parity which is the same drive.

Any advice how to proceed?

Thanks!

Edited June 17, 2017 by pavel.b
I made and mistake in explanation.

[JorgeB]

50 minutes ago, pavel.b said:

Move all data from Disk 1 (500GB SSD) to new parity drive (500GB SSD) = same drive

 

I assume you mean cache, you can just assign it as cache after doing a new config as long as you keep using the same filesystem.

 

52 minutes ago, pavel.b said:

Set SSD Pool

 

Not really a good idea with two different size (and performance) devices, speed and capacity (using the default raid1 profile) will be limited to the smallest and slower of the two.

[pavel.b]

Yes, you are right, I meant the cache drive - fixed.

 

Quote

after doing a new config as long as you keep using the same filesystem

I am not sure what you mean here.

 

I am having two problems:

1) When I remove the current SSD drive the system is requesting to put another drive to its place to rebuild the array from parity. I need a way how to remove it permanently.

2) Is simple copy of the data from SSD to the Disk 2 and then move to the parity SSD back enough to make it work the same way like before? I do not want to broke my previous VMs.

 

Quote

Not really a good idea with two different size (and performance) devices, speed and capacity (using the default raid1 profile) will be limited to the smallest and slower of the two.

Thanks!

[JorgeB]

10 hours ago, pavel.b said:

1) When I remove the current SSD drive the system is requesting to put another drive to its place to rebuild the array from parity. I need a way how to remove it permanently.

 

Tools -> New config -> Retain All - you can then remove or reassign the SSD

 

10 hours ago, pavel.b said:

2) Is simple copy of the data from SSD to the Disk 2 and then move to the parity SSD back enough to make it work the same way like before? I do not want to broke my previous VMs.

 

If you're going to assign the SSD as cache there's no need to copy the data, just assign it to the cache slot using the same filesystem (probably xfs) and all data will bet there.

[pavel.b]

Quote

Tools -> New config -> Retain All - you can then remove or reassign the SSD

 

Got it! Thanks.

 

Quote

If you're going to assign the SSD as cache there's no need to copy the data, just assign it to the cache slot using the same filesystem (probably xfs) and all data will bet there.

1

 

So I tried that and the drive was unmountable (unRAID require to format it) even the filesystem is the xfs.

 

I need to move my VMs from the Disk 1 to Parity drive without breaking stuff. I am not sure that simple copy over will work...

[JorgeB]

If it's unmontable you're doing somethong wrong.

See the replace cache procedure on the FAQ and adapt as needed to move dockers/VMs