Upgrading cache drive.


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Hi all :)

So yes, this have been gone over plenty of times, but can't really decide what would be the safest choice or why.

Running a single 250GB SSD as cache today, just got a new 1TB SSD to replace it as it's running on it's last leg :) From reading different posts, most people refer to this guide: https://wiki.unraid.net/index.php/Replace_A_Cache_Drive

However, a few times, people reference that his would take an insane amount of time as the Mover will check every file, and I have a huge library with hundreds of thousands of files that I'm guessing would take hours, with the array and all my dockers offline?

 

In a few instances, some say that just using the CA Backup/Restore plugin would be enough. I already use this on an automated setup, would it be enough to run this manually, then stop everything, unassign the Cache drive, reboot, assign the new one, then use restore from the backup I just created or will this leave me with something missing and/or needing manual configuration?

 

I do not use any VM, and after a search in krusader, all I can find on my Cache drive today are my appdata, an empty .trash-99 folder and an empty system folder.

 

Regrads :)

 

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5 minutes ago, johnnie.black said:

Then you can do an online replacement, you can continue to use the server normally:

https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=480419

 

Note the bold part about a single device "pool"

Wow ok I totally missed that way of upgrading, thank you :)

Quick question doh, as today I am running my Cache drive on the motherboards sata ports, and the only available sata ports I have are on my LSI controller. Don't think this would matter, but just in case, any thoughts?

And yes, I am running one cache drive, so basically I need to stop the array, click 2 cache drives but only use one, then start it so it's in a "pool" of 1? Then I can proceed with your guide from the link?

 

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2 minutes ago, ProZac said:

Don't think this would matter, but just in case, any thoughts?

Cache will still work, but depending on the controller and SSD it might lose trim support.

 

3 minutes ago, ProZac said:

click 2 cache drives but only use one, then start it so it's in a "pool" of 1? Then I can proceed with your guide from the link?

Correct.

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1 hour ago, johnnie.black said:

Cache will still work, but depending on the controller and SSD it might lose trim support.

 

Correct.

This sounds great, ssd and a new 8tb coming tomorrow, think I will remove an old 1TB drive and put the new SSD cache there as I'm not sure about trim on my LSI controller :) Will ofc do this first, then check that all works before I start to swap the cache drive :) 

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15 hours ago, johnnie.black said:

Cache will still work, but depending on the controller and SSD it might lose trim support.

 

Correct.

Sorry for maybe naging this what I thought was a simple change, but is there any way that I can verify that my 1 cache drive is registered as a "pool"? My main page just lists the drive as before, but if I stop the array, I have selected 2 drives for cache, with slot 2 being empty. Don't really see any changes.
image.thumb.png.3dd7950d7f5408da88eedd0ebce64402.png
 

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If it's using more than one slot it's a pool, but you can check in the syslog, cache will be mounted using the UUID instead of the device, e.g.:

 

not pool

 

emhttpd: shcmd (107): mount -t btrfs -o noatime,nodiratime /dev/nvme0n1p1 /mnt/cache

 

pool

 

emhttpd: shcmd (205): mount -t btrfs -o noatime,nodiratime -U e072aa60-33e2-4756-8496-c58cd8ba6053 /mnt/cache

 

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On 6/11/2019 at 3:57 PM, johnnie.black said:

Then you can do an online replacement, you can continue to use the server normally:

https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=480419

 

Note the bold part about a single device "pool"

Not sure how people manage to f this up hehe. I even made the mistake of not connecting a power cable to one of my drives in the array, everything went smooth. Booted, started array with both ssd's connected but only 1 assigned, made sure all was well, stopped array, changed assigned cache drive, started array. Took about 2min for the new cache to be finished and all my dockers was up and running.
Rebooted and connected the loose power cable and installed a new 8TB drive and disconnected the old cache drive. New 8TB drive is now running preclear and all my dockers are running smooth.  

Thanks a bunch for all the help and support @johnnie.black

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