Raid-0 (2xSSD) + Raid-1 (1xHDD) possible?

1

Is it possible to have the following setup?

2 x SSD (2x128gb) in RAID-0 (for performance)

+

1 x HDD (1x500gb but using 128gb) in RAID-1 (for redudancy)

If so, does the HDD mirror give a decrease of performance in this setup?

I have virtually no experience using RAID in any setup whatsoever, so please forgive my dumbness if applicable.

ropstah

Posted 2012-06-13T16:04:39.147

Reputation: 341

Answers

1

That's like a three-drive RAID-10. You'd just stripe the two 128GB SSDs first, then mirror it with the 512GB HDD. This would also leave ~250GB left over on the larger HDD to use for another partition.

I'm not sure particularly what software/hardware would support it, but you could probably do a software RAID from within Windows (diskmgmt.msc).

You would not lose any performance. A RAID-1 mirror actually brings about roughly double sequential/random read speeds (since there's two drives to read from). Writes are slightly slower though, since a copy of data needs to be committed to both drives.

Of course, be aware if the 500GB SSD fails, you lose everything.

Bigbio2002

Posted 2012-06-13T16:04:39.147

Reputation: 3 804

Thanks for the input, however the 500gb is a HDD, not SSD! I have a Gigabyte P35-DS3P motherboard with RAID builtin. 1. Will the mirroring on a HDD make the SSD striping work as fast as the slowest drive, being the HDD mirror? 2. Is it not possible to re-create the mirror from the striped setup when the 500gb HDD fails? – ropstah – 2012-06-13T16:15:47.490

1I don't think windows software raid supports stacking raid on top of raid, and you would lose a lot of write performance with this setup since writes would have to wait for the slower hdd. – psusi – 2012-06-13T16:20:32.183

@Bigbio2002: From your last edit I make up that recovering is possible from the striped array? :) – ropstah – 2012-06-13T16:24:12.313

Yeah, I misread it. In a RAID-1, if one drive fails, all your data is safe on the other drive. Of course, RAID-1 is not a backup solution. As for performance, RAID controllers typically assume that all drives in the RAID have similar performance characteristics. I couldn't say how yours will perform, but probably not as fast as a full SSD. – Bigbio2002 – 2012-06-13T16:28:37.127

-1

IMHO it is not possible. Oven if it is possible it is not reasonable. At first I do no think that use raid 0 as element of other array are possible, secondly performance of this will be slowed to speed of HDD - negating any sense to use SSD. At RAID 1 the slowest element sets/limits speed of writing.

Tomasz Szczypel

Posted 2012-06-13T16:04:39.147

Reputation: 11