Two Intel X25-M 80GB in RAID0

[Alkapwn]

Greetings everyone.

I read the article on SSDs written by Anand (thank you for such a complete and informative write up!) and have questions about what would be the optimal stripe size for the Intel X25-M if it were setup in RAID 0.

I'm using the X58 controller in my i7 920 PC (yet to be completed). The RAID would be used as an OS/Application drive, with all temp / page / cache / user data moved off to a 300GB velociraptor or a 1TB drive. I'm not really putting these drives in RAID for the increased throughput (it would be a very fortunate side-effect), but rather to obtain the larger 160GB of space. Despite this, I want it to perform as well as possible.

So... Would a 4k stripe be best, as that way the stripe size matches the page size?
-or-
Would a 512k stripe be best, as that way data would be written in sizes which would allow for complete deletions of entire blocks? Can the X58 even be set to a 512k stripe?

I know a smaller stripe typically favors random read/writes, while larger typically favors sequential read/writes. Isn't 4k excessively small, even for SSD? It would be on a normal raid, I think.

Anyone with experience on SSD and RAIDs please help. I want to squeeze all the performance I can out of these drives.

 

[Idontcare]

Originally posted by: Alkapwn
I know a smaller stripe typically favors random read/writes, while larger typically favors sequential read/writes. Isn't 4k excessively small, even for SSD? It would be on a normal raid, I think.

For onboard raid controller where the CPU gets to do a lot of the work of parsing the file stripes the smaller stripe size is going to cost you some notable CPU utilization.

Honestly you are best off to just go with the standard 64KB (or 128KB) stripe size and be done with it.

The potential performance gain to he had from optimizing your stripe size in your case is likely to simply never be noticed by you anyways as the biggest benefit of the SSD's is that low latency and this experience will swamp out all other performance signals your senses might be getting from a tuned raid-0 array.

 

[IBDoomed]

I've done basically the same setup, two 80gb x25's in raid0 on an evga x58 board. I don't believe 512k was an option. I planned this out for weeks and read as much as I could find, much of it going far over my head, and decided on 64k but I'll be damned if I could remember which review convinced me of that. I turned off my page file but have left everything else stock since 160gb is more than enough for my gaming machine. I tested both the onboard and an adaptec 5805 just doing some real world "how fast does it feel" kind of things and decided the onboard felt just as fast (64k stripe on both, cloned the partition so it was identical). I did pay attention to the cpu usage and both controllers were within 1% of each other when executing the same tasks, office, photoshop, fallout3, farcry2, and so on.

 

[Alkapwn]

Thank you both for your replies!

Doomed, thank you for posting your results with this setup. What did your CPU usage look like on this? 5% or more?

I think what I may do is load a quick XP pro installation on it, image the setup, then HD Tach/Everest different stripe sizes and see if there are any differences between 4k and 64k.

 

[IBDoomed]

I didn't do hdtune/tach like I should have, at idle it bounced between 0% and 5% according to the task manager (not real accurate I know) and when loading various apps the spikes looked the same (I recorded them). The time to open groups of apps (all of CS and all of Office) was virtually identical. Enough to make me decide I didn't need the extra heat from the 5805 feeding my video card.