I upgraded some stuff via Black Friday, and now I have a 1TB SATA SSD that I'd like to use as an array drive.  I understand there is no TRIM for array drives.  Otherwise, is this configuration supported?  Is anyone else here doing this?  Also, in order to add this to an existing array, presumably I have to at least do a pre-clear (zero the drive) and have a pre-clear signature written.  Anything else I should be aware of?  Thanks in advance!

40 minutes ago, ufopinball said:

I understand there is no TRIM for array drives.  Otherwise, is this configuration supported?

Yes, you should just run a couple of parity checks after a few days to confirm no parity sync errors.

 

41 minutes ago, ufopinball said:

Also, in order to add this to an existing array, presumably I have to at least do a pre-clear (zero the drive) and have a pre-clear signature written.  Anything else I should be aware of? 

Not really, if you want you could overprovisioned it to help with the lack of trim.

 

Of course writes to that SSD in the parity array will only be at the speed of parity. Why not just use it as an Unassigned Device or add it to your cache pool?

4 hours ago, trurl said:

Of course writes to that SSD in the parity array will only be at the speed of parity. Why not just use it as an Unassigned Device or add it to your cache pool?

 

I have a cache drive.  An array drive means I get Parity protection in case of a drive failure, and cache or UD doesn't offer that.  The performance boost I'm looking for is on the Read end of things.  Writing to this drive will likely be relatively rare, it's just data I don't want to wait for a HDD to spin up for.

Edited December 10, 20187 yr by ufopinball

8 hours ago, johnnie.black said:

Yes, you should just run a couple of parity checks after a few days to confirm no parity sync errors.

 

Not really, if you want you could overprovisioned it to help with the lack of trim.

 

 

Thanks, I will run a parity check here and there to make sure.  The drive was one of my old cache pool drives and has not given me issues.  It's still fairly young, as far as SSDs go.  It's also a 1TB drive and I don't really know that I'll be eating up so much of it, I guess it will come down to usage once I have it installed.  As I mentioned in the other post, this is mostly for quick-access to Read existing data.  It's not going to be a heavy R/W sort of drive (like a cache drive) so hopefully TRIM won't be such a big issue.

Frequent parity checks in the beginning are just to make sure the SSD doesn't cause sync errors with the internal garbage collection function, it should't but it's best to make sure, I already used several SSDs and there was only one (Kingston SV300) that would cause 2 or 3 sync errors after a power cycle, likely not even related to garbage collection, but you still want to make sure there are none, or if another disk fails there will be some corruption on the rebuilt disk.

5 minutes ago, johnnie.black said:

Frequent parity checks in the beginning are just to make sure the SSD doesn't cause sync errors with the internal garbage collection function, it should't but it's best to make sure, I already used several SSDs and there was only one (Kingston SV300) that would cause 2 or 3 sync errors after a power cycle, likely not even related to garbage collection, but you still want to make sure there are none, or if another disk fails there will be some corruption on the rebuilt disk.

Good to know, thanks for the info!

18 minutes ago, ufopinball said:

 

I have a cache drive.  An array drive means I get Parity protection in case of a drive failure, and cache or UD doesn't offer that.  The performance boost I'm looking for is on the Read end of things.  Writing to this drive will likely be relatively rare, it's just data I don't want to wait for a HDD to spin up for.

Cache pool with RAID1 does offer protection. I forgot the command, but I have set up RAID1 cache pool on my system.

3 minutes ago, Harrywong said:

Cache pool with RAID1 does offer protection. I forgot the command, but I have set up RAID1 cache pool on my system.

raid1 is the default setting for the btrfs cache pool so no command needed. Other settings are discussed in the Cache Pool section of the Unraid V6 FAQ

9 minutes ago, trurl said:

raid1 is the default setting for the btrfs cache pool so no command needed. Other settings are discussed in the Cache Pool section of the Unraid V6 FAQ

I had one ssd in the beginning, later I added one for raid1. Had to manually type in the command, because when the second ssd got inserted, the system set up raid0 for the two ssd (unraid 6.6.5).

Edited December 10, 20187 yr by Harrywong

9 minutes ago, Harrywong said:

because when the second ssd got inserted, the system set up raid0 for the two ssd (unraid 6.6.5).

By default Unraid creates a raid1 pool.

25 minutes ago, Harrywong said:

Cache pool with RAID1 does offer protection. I forgot the command, but I have set up RAID1 cache pool on my system. 

Noted, but I already have a RAID1 cache pool (see signature).  SSD capacities are going up and prices are coming down (relatively speaking).  My needs are not so great that I'm out there buying 12TB drives, so someday I'd like to switch over to SSDs.  This may be years in the future, but it may also be a slow migration away from HDD to SSD, depending on how often I access data on any given drive.  I'm not going to RAID1 my 40TB of existing space as SSD, I rather like the current set up with two Parity drives and ten Data drives.

I mean, if you never want to add an SSD to your array, that's fine.  I understand the options available via cache, but I want to do this specifically as an array drive.  Since this configuration appears to be supported, I'll start with a small 1TB SSD and see how things go.

I did see your sig. You can add a 3rd drive to the 'mirror' and so increase its capacity. Just mentioning the options, nothing wrong with your way.

3 hours ago, trurl said:

I did see your sig. You can add a 3rd drive to the 'mirror' and so increase its capacity. Just mentioning the options, nothing wrong with your way.

Oh, okay.  I have not pushed Cache beyond two drives mirrored.  I'll keep it in mind for future reference.  The most I see is people would like the option to have multiple cache pools.  Dunno what priority that has on the wish list.