On Wed, Jun 12, 2024 at 01:04:18AM +0200, Reindl Harald wrote: > > > Am 11.06.24 um 20:31 schrieb Piergiorgio Sartor: > > I'm setting up a system with 2 SSD M.2 (NVME). > > > > I was wondering if would it be better, performace > > wise, to have a RAID-10 near layout or a RAID-1. > > > > Looking around I found only one benchmark: > > > > https://strugglers.net/~andy/blog/2019/06/02/exploring-different-linux-raid-10-layouts-with-unbalanced-devices/ > > > > Which uses mixed SSD, NVME and SATA. > > > > Does anybody have any suggestions, links, or > > ideas on the topic? > > > > BTW, practically speaking, what's the difference, > > between the two RAIDs? > > i wouldn't even consider a RAID10 with two disks, especially with SSD and > practically you end with a unsupported RAID1 because there are no stripes > with 2 disks > Hi, thanks for the answer. I'm a bit confused here. What do you mean with "unsupported RAID1"? As far as I know, but please correct me if I'm wrong, a Linux md RAID-10 *near* layout, with 2 devices, has identical data distribution as a RAID-1 with 2 devices. Meaning the 2 devices are a mirror. The difference, if I understood it correctly, is that the RAID-10 has chunks, and hence stripes, while the RAID-1 does not have stripes. Furthermore, the read operation on RAID-10 are interleaved, delivering (for SSDs) double sequential read speed (for 2 devices), while the RAID-1 can handle two independent (one per device) read stream, each with single device reading speed. Of course, depending on the requirements, assuming what I wrote is correct, performances might be different. I was just wondering if anybody has some hints, some experience, some references, or, as you suggested, not to care at all. Thanks again, bye, -- piergiorgio
