Primarily for VM use I want to build a very fast unraid array with ssds only.

 

The SSDs are server grade NVME SSDs from Samsung - PM9A3 Series.

 

As I read in the UNRAID forum there are concerns regarding "wear" of SSDs. 

 

I read this also regarding PROXMOX and there was always the solution to NOT use consumer SSDs but server / enterprise SSDs that can stand extensive wear without problems.

 

Is this the case with UNRAID, too?

 

 

Array doesn't support trim for SSDs, but that is much less important with enterprise models, both for performance and durability.

I might look at using a ZFS array with the SSDs.  I believe the issue is not putting the SSD into the array but using them for the parity check.  So you can put them in an array without parity (wouldn't recommend) or I think you can (what I'm going to try this week) is making a ZFS pool, setting your array onto a usb device and then using symlinks on the USB folders into the ZFS array.  

Don't know if it will work like that but I think it will.

 

 

14 minutes ago, dirkinthedark said:

I believe the issue is not putting the SSD into the array but using them for the parity check

If they are assigned to the array they cannot be trimmed, even if there's no parity.

15 minutes ago, JorgeB said:

If they are assigned to the array they cannot be trimmed, even if there's no parity.

As far as I understand it server ssds do use trim on their own and do not need any (trim) support by the os - in this case Unraid.

So does this lead to any potential problems?

Like mentioned for enterprise SSDs it's not usually a problem.

The only possible concern I see is that a SSD used for parity (if you have it) would get far more wear than the others as writes to any array data drive would also involve a write to the parity drive so that one would end up with the sum of all the writes to data drives as its own write total.

7 minutes ago, itimpi said:

The only possible concern I see is that a SSD used for parity (if you have it) would get far more wear than the others as writes to any array data drive would also involve a write to the parity drive so that one would end up with the sum of all the writes to data drives as its own write total.

With an enterprise drive this is no problem. Endurance is much higher. Endurance for the Samsung drives is 1,3 DWDP for 3 years. Meantime Between Failure (MTBF) is 2.000.000 hours.

I wouldn't do it. Use a system that treats the hardware in a more as designed matter, with the trim working. Unless the drive manufacturer specifically officially in writing supports operation without trim, and with built-in trim, then run the drive  with the bult in trim. Otherwise simply say No.

 

Why unRAID does not have trim in the Array ? If this is the case just don't use Array. Use them with ZFS or directly.

 

The consumer crap can also do the writes you just need to use the biggest models and write little to them.

 

As well as write to RAM. Just use UPS and write to RAM this is more cost efficient.

Edited February 9, 20233 yr by GRRRRRRR