I am running unRAID 6.1.8

 

So without first researching the issue I stupidly assumed that I could put an SSD into my protected array and use it to store my plex library files  . I wanted to move them off the cache drive as it is an old drive and I wanted the files protected in case the drive failed so I wouldn't have to completely rebuild my library. Browsing around on the lime-tech site today I noticed that this is actually entirely unsupported and could cause data loss due to TRIM.

 

So my question to all you lovely people is what would be my best course of action for removing the SSD from the array? I know there are instructions here but they haven't been updated for unRAID 6 yet so I didn't know if that was still the right way to go about this.

 

My new plan is to remove the old cache drive and replace it with the 250GB SSD and just leave my docker.img and plex files on it. Probably setup an rsync script to run nightly to backup the plex library files in case the drive ever dies.

TRIM would probably invalidate parity but it won’t work on array SSDs, SSD internal garbage collection should not invalidate parity, I tested several models and didn’t have any sync error, best way to be sure would be doing frequent parity checks in the beginning, if there are no sync errors in the first 30 days then I’d say you’re fine, but if you want to remove it from the array then the link you posted is still valid for v6.

TRIM would probably invalidate parity but it won’t work on array SSDs, SSD internal garbage collection should not invalidate parity, I tested several models and didn’t have any sync error, best way to be sure would be doing frequent parity checks in the beginning, if there are no sync errors in the first 30 days then I’d say you’re fine, but if you want to remove it from the array then the link you posted is still valid for v6.

That would be awesome, I was wondering if it would be ok if I just didn't enable TRIM.

From my understanding (after a read through of TRIM on Wikipedia) the only real downside of not having TRIM is a reduction in write speed to the SSD (and drive life) when it is working with blocks that the OS has flagged as free and needs to be overwritten, correct?

That would be awesome, I was wondering if it would be ok if I just didn't enable TRIM.

 

You can't enable it, at the moment FSTRIM it will only work on the cache drive or pool.

 

From my understanding (after a read through of TRIM on Wikipedia) the only real downside of not having TRIM is a reduction in write speed to the SSD (and drive life) when it is working with blocks that the OS has flagged as free and needs to be overwritten, correct?

 

Write speed will degrade without TRIM but on a decent SSD still be much faster than HDD.

 

Still recommend you do frequent parity checks in the beginning, sync errors should always be 0, let us know if you keep it and get sync errors.

From my understanding (after a read through of TRIM on Wikipedia) the only real downside of not having TRIM is a reduction in write speed to the SSD (and drive life) when it is working with blocks that the OS has flagged as free and needs to be overwritten, correct?

 

Write speed will degrade without TRIM but on a decent SSD still be much faster than HDD.

 

Still recommend you do frequent parity checks in the beginning, sync errors should always be 0, let us know if you keep it and get sync errors.

 

Let me just add, as I was not very clear above, that in your case, and assuming your parity is an HDD, write speed will be limited by its speed, SSD will only improve reads.

From my understanding (after a read through of TRIM on Wikipedia) the only real downside of not having TRIM is a reduction in write speed to the SSD (and drive life) when it is working with blocks that the OS has flagged as free and needs to be overwritten, correct?

 

Write speed will degrade without TRIM but on a decent SSD still be much faster than HDD.

 

Still recommend you do frequent parity checks in the beginning, sync errors should always be 0, let us know if you keep it and get sync errors.

 

Let me just add, as I was not very clear above, that in your case, and assuming your parity is an HDD, write speed will be limited by its speed, SSD will only improve reads.

Yes everything in my array is an HDD except for this one disk. I am running a parity check on the array now and will report my results.

 

The write speeds aren't a huge deal to me, the main reason I wanted the SSD for my plex is so it could serve my library information faster and to more people without any hangups from the library infomation itself. I noticed that when the library was on my cache drive even just viewing my own content locally was slow

 

My actual media is spread across enough disks that I don't think I would run into any bottlenecks unless a number of people are all trying to stream from the same disk at the same time (which I think will be rather unlikely).

 

EDIT: Parity check is finished and no errors have been reported. I will keep an eye on it and run a check about once a week for the next couple weeks and see what comes up.

From my understanding (after a read through of TRIM on Wikipedia) the only real downside of not having TRIM is a reduction in write speed to the SSD (and drive life) when it is working with blocks that the OS has flagged as free and needs to be overwritten, correct?

 

Write speed will degrade without TRIM but on a decent SSD still be much faster than HDD.

 

Still recommend you do frequent parity checks in the beginning, sync errors should always be 0, let us know if you keep it and get sync errors.

 

Let me just add, as I was not very clear above, that in your case, and assuming your parity is an HDD, write speed will be limited by its speed, SSD will only improve reads.

Yes everything in my array is an HDD except for this one disk. I am running a parity check on the array now and will report my results.

 

The write speeds aren't a huge deal to me, the main reason I wanted the SSD for my plex is so it could serve my library information faster and to more people without any hangups from the library infomation itself. I noticed that when the library was on my cache drive even just viewing my own content locally was slow

 

My actual media is spread across enough disks that I don't think I would run into any bottlenecks unless a number of people are all trying to stream from the same disk at the same time (which I think will be rather unlikely).

 

EDIT: Parity check is finished and no errors have been reported. I will keep an eye on it and run a check about once a week for the next couple weeks and see what comes up.

So a follow up to this if anyone is interested I have been running with a single SSD as part of my array for a few months now and have noticed no issues with parity errors or any other data integrity issues.

Without further testing I don't want to make any sort of absolute statement but it appears that you can have SSDs in your array as long as you don't have TRIM enabled on them. If anyone else would like to weigh in on there experiences with this sort of configuration I'm sure it would be helpful to the community.