I'm thinking of adding a SDD to my array as my first cache disk, but have a few questions:

1. I understand that the web interface should ask me if the new disk should be added to the storage or cache array, but since this is an existing array how do I properly move my existing appdata folder to the cache drive without breaking anything with the docker apps?  I read that I should mark the "appdata" folder as "cache only", but will that cause any problems?  Will this cause the folder to be moved to the cache disk automatically or do I need to copy any contents manually?

2. Are the contents of the cache drive ever backed up (i.e the appdata folder)?  I understand that data that is written to the array will be temporarily stored on the cache drive until it does a nightly dump to the redundant array.  But what I'm unsure of is if the appdata folder itself is backed up?  I also understand that I could add a second SSD as part of a cache array for immediate redundancy, but I was hoping the appdata folder would also get synced to the data drives nightly as well…

3. Given these drawbacks to using a cache disk, the main advantage I'm hoping to get out of adding a SSD is that it will allow my HDDs to spin down when not in use so as to extend their life.  I just want to verify that the spindown will happen.  Am I correct?

Thank you!

I'm thinking of adding a SDD to my array as my first cache disk, but have a few questions:

1. I understand that the web interface should ask me if the new disk should be added to the storage or cache array, but since this is an existing array how do I properly move my existing appdata folder to the cache drive without breaking anything with the docker apps?  I read that I should mark the "appdata" folder as "cache only", but will that cause any problems?  Will this cause the folder to be moved to the cache disk automatically or do I need to copy any contents manually?

Set the appdata folder to be useCache "prefer" and then run mover from the Main tab.  It'll then get moved over automatically

2. Are the contents of the cache drive ever backed up (i.e the appdata folder)?  I understand that data that is written to the array will be temporarily stored on the cache drive until it does a nightly dump to the redundant array.  But what I'm unsure of is if the appdata folder itself is backed up?  I also understand that I could add a second SSD as part of a cache array for immediate redundancy, but I was hoping the appdata folder would also get synced to the data drives nightly as well…

Set up CA's Appdata Backup / Restore module to perform scheduled backup of the appdata folder to the array.  (And it also offers dated backups so in the event of a screwup somewhere in the future, you can choose which backup set to restore from)

3. Given these drawbacks to using a cache disk, the main advantage I'm hoping to get out of adding a SSD is that it will allow my HDDs to spin down when not in use so as to extend their life.  I just want to verify that the spindown will happen.  Am I correct?

Yes

Perfect, thanks so much Squid.  I found the Appdata Backup docker in the Community Apps. 

EDIT: FIXED!! nevermind.  I changed the formatting to BTRFS and then when I started the array it told me the disk was unmountable and gave me the format button.  I guess it wasn't clear because the instructions say to use BTRFS if you are creating a cache "pool".  Since I'm only adding one drive it's not really a pool.  Anyway, I thought since it was set to auto it would choose BTRFS anyway.  Ok onto the next step...

 

Ok I just got around to adding the disk to the array and I ran into a problem.  The only thing I've done is plug in the disk, boot UnRAID, assign the disk to cache, and start the array.  The problem is UnRAID is saying the SSD is only 524 MB in size when it should be 128 GB.  This guide page (http://lime-technology.com/wiki/index.php/UnRAID_6/Getting_Started#Assigning_Devices_to_the_Array_and_Cache) says I need to:

New devices added to disk or cache device slots will appear as 'Unformatted' and will be unusable until you format them. unRAID 6 defaults to using the XFS filesystem for all devices, but if you define a cache pool, BTRFS will automatically be used for those devices. To format your devices for use, you must click the check box under ‘Array Operation’ that says Format and then click the Format button.

However, I don't see this Format button.  Perhaps I need to format to get it to recognize the drive properly?  The SSD does have a partition already from my previous computer, but I want to wipe all of that data.  Any help?  Thanks.

The fact that the SSD was partitioned and used in another computer is probably causing the discrepancy in reported size. You need to remove all partitioning and then format it within unRAID. If you have the Pre-clear plugin installed you could run a single cycle on the SSD to achieve that. You'll need to unassign it from the cache slot first, and reassign it once the pre-clear has finished. Normally I wouldn't suggest pre-clearing an SSD but in this case it should get you where you want to be.

The fact that the SSD was partitioned and used in another computer is probably causing the discrepancy in reported size. You need to remove all partitioning and then format it within unRAID. If you have the Pre-clear plugin installed you could run a single cycle on the SSD to achieve that. You'll need to unassign it from the cache slot first, and reassign it once the pre-clear has finished. Normally I wouldn't suggest pre-clearing an SSD but in this case it should get you where you want to be.

Thanks, I was able to get through the formatting without preclear.  So the SSD appears to be working, but I'm stuck at the next step.  When I open my Shares and click on the "appdata" share I set "use cache disk" to "yes" (I thought "yes" would be better than "only" because my appdata share may be larger than the SSD?).  Then I click the "mover" button on the main tab, but nothing happens.  If I watch the Log while I click Mover I see "mover started" and immediately followed by "mover finished".  Why isn't that moving the data? What am I forgetting?  Or do I need to set the "use cache disk" to "only"?

Set the share to "prefer" and run the mover.

Thanks, I was able to get through the formatting without preclear.  So the SSD appears to be working, but I'm stuck at the next step.  When I open my Shares and click on the "appdata" share I set "use cache disk" to "yes" (I thought "yes" would be better than "only" because my appdata share may be larger than the SSD?).  Then I click the "mover" button on the main tab, but nothing happens.  If I watch the Log while I click Mover I see "mover started" and immediately followed by "mover finished".  Why isn't that moving the data? What am I forgetting?  Or do I need to set the "use cache disk" to "only"?

the value of 'yes' means write new files to cache, and when mover runs they are moved to the array.  You may have to use that if you think your appdata might be larger than the cache disk, but you will take a performance hit as accessing the files on the array disks is significantly slower.  If you already have share files on the array disks then setting it to 'prefer' will cause mover to move the files from the array disks to the cache disk.  If set to 'only' then all new files are written to the cache disk and mover will not move them to the array disks.

Ok, yeah I noticed that Squid told me to use "prefer" but I don't have that option (so I assumed maybe he just mis-remembered what it's called).  For "use cache disk" I have the options: No, Yes, and Only.  I'm running UnRAID 6.1.8 if that makes a difference.

 

Actually I just used UnRAID to calculate the size of the appdata folder and it is only 24.2 GB.  I used Windows Explorer to calculate it yesterday and I can't remember exactly what it said but it was very large... anyway that shouldn't be an issue.  So which option tells it to always and only use the cache disk?  Only?

 

edit: some files have moved to the cache disk.  I'm assuming these are newly created files.

Ok, yeah I noticed that Squid told me to use "prefer" but I don't have that option (so I assumed maybe he just mis-remembered what it's called).  For "use cache disk" I have the options: No, Yes, and Only.  I'm running UnRAID 6.1.8 if that makes a difference.

 

Actually I just used UnRAID to calculate the size of the appdata folder and it is only 24.2 GB.  I used Windows Explorer to calculate it yesterday and I can't remember exactly what it said but it was very large... anyway that shouldn't be an issue.  So which option tells it to always and only use the cache disk?  Only?

 

edit: some files have moved to the cache disk.  I'm assuming these are newly created files.

6.1.8 isn't even available for download anymore. You will get better support if you upgrade to the latest stable version. And you would be able to set cache-prefer and get your appdata automatically moved to cache.

Thanks everybody.  I upgraded UnRAID and I see the updated option for "prefer".  Mover is now moving the files but it'll take a while.  I'll come back if that runs into any problems or if I have questions about setting up CA's Appdata Backup / Restore module.

The Disk 1 and the Parity drive won't spin down.  I spun disk 2 down manually and it has stayed spun down.  How do I diagnose what's keeping the other two disks awake?

The global spin down timer setting (Settings -> Disk Settings -> Default spin down delay) can be over-ridden by settings for individual disks (Main -> Disk N -> Spin down delay). Is this set to 'Never'?

 

The global spin down timer setting (Settings -> Disk Settings -> Default spin down delay) can be over-ridden by settings for individual disks (Main -> Disk N -> Spin down delay). Is this set to 'Never'?

Ok thanks, I couldn't find the default setting before.  Each disk was set to default, but I wasn't sure what that was.  I just assumed the default would be at most an hour or two.  But the global default was set to never, so I just updated to to 1 hour.  That should do it, thanks.

I think what might be keeping the Disc 1 and Parity drives spun up is that the docker image file is still on disk 1.  I should move this to the cache disk in order to get those drives to spin down, right?  Based on this it looks like I should just take the dockers offline and cut/paste the docker image onto the cache file?  Does that sound right?

http://lime-technology.com/forum/index.php?topic=47159.msg451295#msg451295

I think what might be keeping the Disc 1 and Parity drives spun up is that the docker image file is still on disk 1.  I should move this to the cache disk in order to get those drives to spin down, right?  Based on this it looks like I should just take the dockers offline and cut/paste the docker image onto the cache file?  Does that sound right?

http://lime-technology.com/forum/index.php?topic=47159.msg451295#msg451295

Yup (and adjust the settings for Docker to point to the new location before restarting the service)

 

Alternatively, if the docker.img is in its own share, you can set the useCache settings on the share to be "prefer", stop the docker service, run mover, then restart the service (after verifying the default location for the docker.img is pointed correctly)

I think what might be keeping the Disc 1 and Parity drives spun up is that the docker image file is still on disk 1.  I should move this to the cache disk in order to get those drives to spin down, right?  Based on this it looks like I should just take the dockers offline and cut/paste the docker image onto the cache file?  Does that sound right?

http://lime-technology.com/forum/index.php?topic=47159.msg451295#msg451295

If your docker.img is in a cache-prefer share then mover would have skipped it since it was open. Stop docker service (not individual dockers) and run mover again.

 

If instead docker.img is at the root of a disk then you will have to move it yourself.

After moving the file and updating the file path I got this error:

Your existing Docker image file needs to be recreated due to an issue from an earlier beta of unRAID 6. Failure to do so may result in your docker image suffering corruption at a later time. Please do this NOW!

So that looks like I should just click the "delete image file" button and reinstalling the dockers?

After moving the file and updating the file path I got this error:

Your existing Docker image file needs to be recreated due to an issue from an earlier beta of unRAID 6. Failure to do so may result in your docker image suffering corruption at a later time. Please do this NOW!

So that looks like I should just click the "delete image file" button and reinstalling the dockers?

Yes. From Community Application you can select your Previous Apps and they will be recreated just as before.

After moving the file and updating the file path I got this error:

Your existing Docker image file needs to be recreated due to an issue from an earlier beta of unRAID 6. Failure to do so may result in your docker image suffering corruption at a later time. Please do this NOW!

So that looks like I should just click the "delete image file" button and reinstalling the dockers?

Yes. From Community Application you can select your Previous Apps and they will be recreated just as before.

Thanks, worked like a charm for Plex and CrashPlan.  The docker for TVheadend isn't working, but I haven't used that docker in a while so I'm not positive it was even working before I started all this (I've had it disabled for the past few months).

After moving the file and updating the file path I got this error:

Your existing Docker image file needs to be recreated due to an issue from an earlier beta of unRAID 6. Failure to do so may result in your docker image suffering corruption at a later time. Please do this NOW!

So that looks like I should just click the "delete image file" button and reinstalling the dockers?

Yes. From Community Application you can select your Previous Apps and they will be recreated just as before.

Thanks, worked like a charm for Plex and CrashPlan.  The docker for TVheadend isn't working, but I haven't used that docker in a while so I'm not positive it was even working before I started all this (I've had it disabled for the past few months).

I think TVheadend requires the DVB build of unRAID. *edit* or maybe not.