We have a SuperMicro X9SRI-F-O board that has two 6gb/s SATA3.0 ports. We currently have a single Samsung 840pro SSD hooked up to the first SATA channel. We want to double the storage and bandwidth by adding another 840pro to the other SATA channel and striping our reads/writes with RAID0.

I checked the block diagram for the motherboard, it appears the southbridge has enough bandwidth to support this setup. We'll benchmark this to make sure, and add a controller card if necessary.

First, our current SSD we don't have discard in the fstab, we simply run trim as a daily cron job. The command is fstrim -v / 2>&1 | logger -t trim. Will this work in a RAID setup?

Second, stripe size seems like a critical decision with an SSD. I've read this should be 64kb per SSD due to erase block size... leading me to think that 128k is the minimum correct stripe size. Eh?

Third, we planned to have the raid partitions use the entire SSDs. I suspect we no longer have to worry about partition alignment, since any partitions(swap) will be on top of the virtual raid device. My other thought is there may have to be a boot partition, since it's unlikely we'll have RAID0 support at boot. If this is the case, how do we align the boot and the main partition for this particular SSD?

Answers to any of these questions or advice, caveats etc is much appreciated. Thank you!


Tested in Ubuntu 14.04 trusty tahr

1) Using the whole disk, fstrim works!

2) No clue as to the correct answer here. Went with 512K.

3) No alignment problems by using the whole disk, confirmed by parted align-check opt.

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