SSD for VM storage

[jtl]

Hello

I apologize if this is the wrong forum for this

I'm looking into adding dual SSD's in ZFS RAID 1 to my server for storing VM's. I have the 4 WD RED 3TB drives in ZFS RAID 10 my server as a NAS (running Samba on host) along with storing VM's and the performance isn't the best (only 40-70mb/s dd tested in Linux guest)

Of these two SSD's, which one would you recommend?

https://www.newegg.ca/Product/Produ...&cm_re=intel_480gb_ssd-_-20-167-382-_-Product
https://www.newegg.ca/Product/Produ...m_re=crucial_525gb_ssd-_-20-156-151-_-Product

Also if anyone has any ZFS tuning advice from stock in context of VM storage and SSD's that would be great.

Thanks.

 

[Rhinox]

None of the above. If you can not use industry-level SSD (which I'd recommend strongly), at least pick one with MLC-NANDs...

 

[kobuki]

Both of these are MLC NAND technology.

However, the most important distinction is that the Crucial MX300 has internal power loss protection capacitors. That's very important for server usage. Between these two, definitely the Crucial. Or get some Intel DC S3500 drives used if you want to go the cheap route.

40-70 MB/s with what kind of load?

 

[Rhinox]

Both of these are MLC NAND technology.

"...Intel 540s Series 2.5" 480GB SATA III TLC Internal Solid State Drive (SSD) SSDSC2KW480H6X1..."

What do you think that "TLC" stands for? BTW, that second one is using TLC-NANDs too...

 

[kobuki]

TLC (Triple Level Cell) is a variant of MLC (Multi Level Cell). That distinction is getting less important as technology advances but in a sense you're righ, since TLC used to refer to 3L cells only.

 

[Rhinox]

Using the same logic we could say MLC is "just" variant of SLC. Then all SSDs are SLC, right?

I do not think so. There is big difference between SLC/MLC/TLC NANDs, and I would never recommend using SSD with TLC-NANDs for PVE. Just search this forum for posts concerning problems with "health" status (bytes written counter) of various consumer-level SSDs falling down quickly with PVE. There are at least a few threads on that topic here.

If OP wants to avoid such a problem, I recommend to use industry-level SSD (SLC/MLC) or at least quite good consumer-SSD with MLC-NANDs. That's why I do not recommend to use any of those two SSDs he mentioned (although the better one of them is trully MX300)...

 

[kobuki]

Your logic is just play of words. SLC was first. Technology is irrelevant nowadays, the important is proven reliability, using whatever type of cells. If you read my first post, you'll see I also recommended an enterprise drive.