Auto TRIM on D3-S4610

basstscho

Cadet
Joined
Jun 9, 2020
Messages
5
I have a TrueNAS-12.0-U3.1 installation with some Pools of Intel SSD D3-S4610 (3.84 TB) - directly connected over an HBA. They are only used for an ESXI-Datastore over NFS. Everything runs fine. One question came up: Do I have to enable Auto TRIM? I have read different things about:

- It's necessary to protect the SSDs
- It slows down the Pool
- It's not necessary in "business" SSDs

Since this is a productive system, I don't want to play around. Is there a recommendation? If it would be useful, I'm wondering why it is not enabled by default.

Thank you and best regards,
Johannes
 

jgreco

Resident Grinch
Joined
May 29, 2011
Messages
18,681
There's nothing magic about "business" (presumably you mean "enterprise") SSD's, except that they tend to have a larger reserve of flash for the free page pool.

SSD's can slow down if they have to work on garbage collection when they are under pressure due to a lack of pages in the free page pool. The rest of the time, blocks are being erased in the background. What this means is that if you do not have a storm of write I/O being pushed out, you can often let the SSD just self-manage things and write speeds will be fine for moderate write levels.

However, if you are cramming huge amounts of data out there, the free page pool will evaporate fast, and in such cases, TRIM gives you a definite advantage because it proactively tells the SSD additional sectors of mapped data which may be considered "available" to the garbage collector and transformed back into free pages. This increases the free pool size, increasing the length of time you can be shoveling data at the SSD at max speed.

https://arstechnica.com/information...revolution-how-solid-state-disks-really-work/

is a good basic reference for how the garbage collection stuff works.

Those drives are rated for 15.2PBW or about 4,000 write cycles, on a 5 year warranty. If you were to fill and erase the entire drive twice a day for the entire warranty period, you might begin to approach this. If you are doing very stressful development work with tons of deploy/destroy cycles of lots of VM's, then you may want to look at this more. Otherwise, if the performance is acceptable as-is, I wouldn't worry too much.
 

basstscho

Cadet
Joined
Jun 9, 2020
Messages
5
Thank you for this really detailed answer. It cleared all my questions and I rate it as not necessary to enable the Auto Trim, since I write in average only 20-100 GB per day on each drive. So the SSD should have more than enough time for it's internal operations.
 
Top