Yeah, that's a very bad idea. It doesn't have power loss protection, so it's useless as an SLOG device. You'd be better off turning off sync writes and getting better performance for the same data protection.
I tried to find some high performance/high endurance drive that explicitly stated it had power loss protection, which I did find some, however they were a bit out of my budget being usually $300+.
I do have two questions though...
Regarding disabling turning off sync writes, I was under the impression, from articles warning against turning it off saying that it was very dangerous with respect to data integrity, that in the case of an application writing "data" to disk and then reading that same "data" before it was flushed to the actual storage disks that the old "data" would be returned instead, potentially causing data corruption.
I just recently found one article that said ZFS will store data not yet committed to disk into system memory, and act as a kind of "overlay" to the storage pool, where in a scenario such as the one above, requests to read the data not yet committed would be read from the "overlay" instead of the storage pool, which would prevent data corruption due to reading old data.
I would assume the second one would be more "true", is the correct?
Also, for the power loss protection issue...
I went through
@Constantin's awesome links (Thank you by the way!) and was kind of wondering about both of your opinions on whether it might be a more cost-effective route by simply buying an UPS? They can be a little pricey, but just kind of wondering that if I get an UPS and have it to simply shutdown my server after a minute or two of power loss, FreeNAS would then have time to flush all uncommitted writes to disk and power off, versus buying the more expensive higher-tier drives that include power loss protection, would the UPS generally be more cost-effective in the long-run? My server also has redundant power-supplies in case one fails as well. But that way I can buy the <$80 NVMe drives a little more safely? XD
As
@Ericloewe pointed out, you ideally want a device with power-loss protection. Some SSDs offer that, so do very expensive Optane options like the 4800X series from Intel. Or, you can gamble and go for a m.2 based Optane offering that doesn't have any DRAM chips and hope that your number never comes up (it's quite unlikely). In that case, consider the Optane 905P series. If I were to build today, I'd likely choose the slightly older but cheaper 800 series of Optane instead.
I definitely appreciate the recommendations, but holy guacamole, the 905P is more expensive than what I paid for my entire server, haha! Not to say that it isn't worth it, but unfortunately I have to budget a bit since I'm still in college and don't have a "real" job yet :P
I'm sure you'd probably be hesitant to recommend anything that would go against best practices, which I definitely understand. But I guess would you say that for the sub-$80 price of the Samsung 970 EVO, would it be worth the investment?
I don't have mission-critical stuff anywhere on my FreeNAS, and have daily backups to Backblaze B2 storage, so worst-case scenario seems like it would just take me a while to fix whatever broke, and if my data is lost locally, I pay the expense of downloading from Backblaze.
...but ONLY if the m.2 slot is actually a PCIe 3.0x2 or higher. Otherwise, you may spend a lot of money for a high-bandwidth Optane product only to get hobbled by a slow bus interface. For the time being, I am very happy with my dual S3710 SSD setup, which doesn't break speed records but is mirrored and fairly robust. My L2ARC drive is a leftover Samsung 840 drive.
True, I did see a few M.2 drive variations that were a bit cheaper, and found out that they only used two PCIe lanes instead of the usual 4, haha. And to this, I'm curious what you think of the UPS proposition as well.
Thank you
@Ericloewe and
@Constantin!
