I'm considering what kind of SSD (SATA SSD or NVME SSD) to buy for the parity check, I'm using a 4 drive micro server and my current disks are:

1. 2TB Samsung 860 EVO (SSD)
2. 2TB Curcial MX500 (SSD)
3. 5TB WD Black (HDD)
4. 5TB Seagate Barracuda (HDD)

Disk 3 and disk 4 are not in the array but mounted with "unassigned devices plugin" to do the backup every week (disk 3) and every month (disk 4), so the parity disk to buy as the parity disk only works with those two SSDs.

So my question is that does the parity check speed depend on the reading speed of the data disks? (I think it should, but not that certain)

Will there any difference for the parity check on one SATA SSD vs NVME SSD?

Edited February 25, 20215 yr by tgeng

3 hours ago, tgeng said:

So my question is that does the parity check speed depend on the reading speed of the data disks? (I think it should, but not that certain)

Yes, it will never be faster than the slowest device in the array.

3 hours ago, JorgeB said:

7 hours ago, tgeng said:

So my question is that does the parity check speed depend on the reading speed of the data disks? (I think it should, but not that certain)

Yes, it will never be faster than the slowest device in the array.

 

@tgeng, you should also realize that the Parity disk is one of the members of the "array" that @JorgeB is referring to.   For the maximum write speed of data to the array, the Parity drive will have to be an SSD which is as fast of the slowest of your data storing disks.  This statement is also true for any operation which involves the Parity drive.

11 minutes ago, Frank1940 said:

 

@tgeng, you should also realize that the Parity disk is one of the members of the "array" that @JorgeB is referring to.   For the maximum write speed of data to the array, the Parity drive will have to be an SSD which is as fast of the slowest of your data storing disks.  This statement is also true for any operation which involves the Parity drive.

Indeed, parity disk is part of the "array".

I tried use one of 5TB HDD disks as the parity, but the parity check will go through the entire 5TB instead of first 2TB or something like that, too slow to take, that's why I'm using them as backup.

Now I can confirm that I don't have to go get the NVME SSD, just SATA SSD is enough.

47 minutes ago, tgeng said:

Now I can confirm that I don't have to go get the NVME SSD, just SATA SSD is enough.

 Not quite true.   A quick Google of   nvme ssd vs ssd   will provide you with several sites about the differences between these two ways of connect an SSD to computer. 

 

Let me provide a quote from one article that I found  (    https://www.promax.com/blog/nvme-vs-ssd-speed-storage-mistakes-to-avoid   )   :

 

Quote

NVMe is not affected by the ATA interface constrictions as it sits right on the top of the PCI Express directly connected to the CPU. That results in 4 times faster Input/Output Operations Per Second (IOPs) rivaling the fastest SAS option out there. The seek time for data is ten times faster. NVMe can deliver sustained read-write speed of 2000MB per second, way faster than the SATA SSD III, which limits at 600MB per second. Here the bottleneck is NAND technology, which is rapidly advancing, which means we’ll likely see higher speeds soon with NVMe.

 

Edited February 25, 20215 yr by Frank1940