New answers tagged software-raid
The best way is as Darren Cook mention in his answer; however, the SuSE way is as follows: Use YaST (yast disk) to set it up through all of the menus and prompts. I would strongly recommend using hardware RAID (purchasing a RAID card) instead of software RAID. My personal experience (and I'm no expert in RAID) has been that software RAID always fails.
Yes. The software to use is called mdadm, and I have done exactly what you describe. (In fact I put a 1TB second disk in, and just created an unmirrored partition with the rest of the space; so it can actually be quite flexible.) Basically you create the raid array with just your current disk. Then you add the new disk to the software array, ask it to copy ...
I assume you did a fresh install and added the drives to the new computer. First do a: mdadm --assemble --scan and look in /proc/mdstat if the array has been activated. Then run: mdadm --examine --scan >> /etc/mdadm/mdadm.conf to get the config information in your new mdadm.conf again.
It's clean, that's good. It's inactive, that's not bad. Take a look e.g. here
RAID10 does not accelerate any form of O_*SYNC, at least not for small files. You're writing 512b at a time, and after each write forcing it out to disk (plus the metadata required to read it back, e.g., file size). That requires RAID10 writes to at least 2 disks, probably 4 (i.e., all your disks). And all those writes need to be completed before it can ...
You're not doing "100b" (byte? blocks? what was your intention?) chunks, you're doing 512 byte chunks. That is always slow because the RAID is using 512k chunks. That means that for every 512 bytes the RAID system has to read a 512k chunk, update 512 bytes in that chunk, compute its parity, and write the data + parity out to disk. It has to do the update, ...
Your dd command gives me 73.7 kB/s - on a SSD. So yes I guess it's normal. Or rather, dd just isn't a good benchmark. RAID certainly does not do any speedups for small files. Access times still remain the same, and for a small file that's what will take most of the effort for HDDs, getting the read head to the physical address of the file in the first place ...
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