At the beginning of the year, the space on my NAS became relatively tight and I would have had to upgrade at least one hard disk in the RAID. That’s why I have investigated if it makes sense to change the NAS operating system.
Until now I have been running an OpenMediaVault server as my NAS. Unfortunately, I replaced some hard disks during the pandemic, but they turned out to be SMR disks only later. I therefore reconfigured the server last year, as the read and write speeds were far from the capabilities of a GBIt LAN.
Then came the 10GBit network, where I then tried to use BCache to achieve better read/write rates. This worked in principle, but I could only set up the BCache with a RAID5, and here the expansion of the RAID’S takes felt eternities.
I have therefore searched to see if I could find a system that would better meet my needs.
First try out
To try out the different options I created a virtual machine and created 6 drives there. The boot drive was only 8 GB, while the data drives were each created with 20 GB.
The point was simply to try out the option once beforehand if possible. And you can do that very well with a VM.
But then I still verified some results after setting up the VM test systems via a real installation, at that time still with 10GBit network.
Openmediavault with RAID5
On the one hand, this is probably the easiest combination to set up and gitl actually as a standard, if you want to have a system where a disk may fail in case of need.
Also from the speed, such a combination can really be seen, because you can really use almost 10G in write mode. In read mode, however, the speed is quite slow with under 500MB/sec.
These were the tests of Crystaldisk. If you try the same with one or more large files, the result looks different. I copied a video project with a total of 21.395.158.775 bytes, and the result is 324 MB/sec. in write mode and 427 MB/sec. when the disks of the raid are empty.
Openmediavault with Snapraid
The advantage of this method is that the hard disks in the group may have different sizes and depending on the storage strategy a complete file always ends up on a certain disk.
That is in the case of a case an advantage, since e.g. with a RAID5 a file which can be stored is divided into blocks and these are stored across all non removable disks of the group.
However, this has consequences for the speed, which is rather disappointing for a 10 GBit connection.
Copying the same video project with a total of about 21 GB to the system results in just under 320 MB/sec for writing and only 170 MB/sec for reading. The first value should be explained by the RAM, which is basically used as cache under Linux.
With further systems it goes then in the 2nd part further.