Hello out there,
One night, I woke up, and sat up in bed realizing an idea (I do that sometimes). What about making a striped raid of USB Memory sticks? Could that be done?
Googled around but couldn't find much on the subject. Next day I went to my local hardware pusher and told him about my idea. He smiled an handed me a couple of cheap kingston 1 GB DataTravelers asking me to come back and tell about my experiences
Connected 4 sticks to a cheap Trust 7port USB Hub, striped them as raid0 in disk utility and Eureka!!! 52 whopping MB/s Read speed! These were slow sticks. Standard formatted they max ran 15 MB/s. Not bad. Writing was slower, about 20 MB/s, but still these sticks were slow.
Today I bought two 8 GB A-Data PD7 200x sticks and they perform pretty well. About 50 MB/s with two striped sticks. They are dirt cheap. About 25$ each. But they are "ReadyBoost" certified for Vista, wich means they promise 30 MB/s read and 20 MB/s write.
2x8 means 16 GB. Hmm... Leopard takes about 15 GB... I had to try that.
Smack! Entered the OS X DVD, restarted, went to Disk Util and selected my FlashRaid as my install drive. I must admit installation wasn't fast. About two hours. BUT It works! I love my
! ;-)
As expected with only two sticks, the performance is not very fast, but it's absolutely possible to work on the computer. How does it feel? Different! No lack due to no latency and very low access times. In fact I'm running OS X from the sticks as i write this.
Next thing was to order 6 more sticks and an extra Trust HUB. That should, in theory, give me a 250$ 64 GB SSD drive with a pretty good performance. Possibly close to 100 MB/s RW, if they are connected carefully to two different USB Bus'. Last one is important because one USB bus is limited to 480 Mb/s, about 60 MB/s. In your system profiler you can see what stick is connected to what bus.
Caution!!! If you want to try this at home, be aware! Flash ram have a limited number of writes! I have no idea wether this is going to work for very long. So far I've been running for two hours... But I'll keep you updated! Anyways, one of the advantages of this drive is that it'll probably fail during write and not during read. I have yet to try a raid5 solution, but I've got Time Machine active (excellent backup software, btw!).
Finnaly: I'm pretty new to the Mac world. Having been a hardcore PC user for 25 years I've had my iMac7,1 for about a year. And i absolutely love it! Leopard is a fantastic OS, and things like Expose and Cowerflow are excellent productivity tools. Many things are like windows, but it's all the smooth details! I've been amazed for a year now. I still work in XP and Vista (shame on you, Microsoft!!!) sometimes... XP is like driving a 1980's small Toyota, Vista is like watching your sports car that only runs on one cylinder, whereas Leopard is a Pagani Zonda on steroids I personally prefer the Zonda to the Toyota ;-) So much for the price of the Mac.
Now it's time to reboot to XP and play some RACE DRIVER - GRID ;-D Ahem, games for mac anybody?!?
Stay cool... One day the DOW will be up again...
Regards
Morten Balling,
CPH-DK
Update: I've been playing some more and found a few a few interesting things. First of all: I Honestly think this will work once I get the 6 extra sticks that I've ordered. It's very important that all the sticks match each other speed vice. The final performance of the raid decreases a lot if only one stick is slow. Think of it as the classic thing with the chain and the weakest link. I benchmarked all the sticks I had separately and found a 8 GB Kingston that matched the two A-data i've got. Added that to the raid running OS X (new install needed). Strangely enough that helped a lot. There's a huge difference running on three sticks in stead of two. I've tried a lot of raids with harddrives and normally you have to have 2,4,8 etc to see an improvement (three HDD's gives the same performance as two but with a more steady performance across the drives once they get filled up). Running OS X on three sticks is perfectly doable, and I'm really looking forward to seeing what 8 similar sticks will do... From the testing I did yesterday it seems that the system is pretty scaleable, meaning that adding more sticks should mean equally better performance
A question: Does anybody know how the USB ports are routed to the USB busses? I have a 24" iMac7,1 Intel Core 2 Duo.
One night, I woke up, and sat up in bed realizing an idea (I do that sometimes). What about making a striped raid of USB Memory sticks? Could that be done?
Googled around but couldn't find much on the subject. Next day I went to my local hardware pusher and told him about my idea. He smiled an handed me a couple of cheap kingston 1 GB DataTravelers asking me to come back and tell about my experiences
Connected 4 sticks to a cheap Trust 7port USB Hub, striped them as raid0 in disk utility and Eureka!!! 52 whopping MB/s Read speed! These were slow sticks. Standard formatted they max ran 15 MB/s. Not bad. Writing was slower, about 20 MB/s, but still these sticks were slow.
Today I bought two 8 GB A-Data PD7 200x sticks and they perform pretty well. About 50 MB/s with two striped sticks. They are dirt cheap. About 25$ each. But they are "ReadyBoost" certified for Vista, wich means they promise 30 MB/s read and 20 MB/s write.
2x8 means 16 GB. Hmm... Leopard takes about 15 GB... I had to try that.
Smack! Entered the OS X DVD, restarted, went to Disk Util and selected my FlashRaid as my install drive. I must admit installation wasn't fast. About two hours. BUT It works! I love my
! ;-)As expected with only two sticks, the performance is not very fast, but it's absolutely possible to work on the computer. How does it feel? Different! No lack due to no latency and very low access times. In fact I'm running OS X from the sticks as i write this.
Next thing was to order 6 more sticks and an extra Trust HUB. That should, in theory, give me a 250$ 64 GB SSD drive with a pretty good performance. Possibly close to 100 MB/s RW, if they are connected carefully to two different USB Bus'. Last one is important because one USB bus is limited to 480 Mb/s, about 60 MB/s. In your system profiler you can see what stick is connected to what bus.
Caution!!! If you want to try this at home, be aware! Flash ram have a limited number of writes! I have no idea wether this is going to work for very long. So far I've been running for two hours... But I'll keep you updated! Anyways, one of the advantages of this drive is that it'll probably fail during write and not during read. I have yet to try a raid5 solution, but I've got Time Machine active (excellent backup software, btw!).
Finnaly: I'm pretty new to the Mac world. Having been a hardcore PC user for 25 years I've had my iMac7,1 for about a year. And i absolutely love it! Leopard is a fantastic OS, and things like Expose and Cowerflow are excellent productivity tools. Many things are like windows, but it's all the smooth details! I've been amazed for a year now. I still work in XP and Vista (shame on you, Microsoft!!!) sometimes... XP is like driving a 1980's small Toyota, Vista is like watching your sports car that only runs on one cylinder, whereas Leopard is a Pagani Zonda on steroids
I personally prefer the Zonda to the Toyota ;-) So much for the price of the Mac.Now it's time to reboot to XP and play some RACE DRIVER - GRID ;-D Ahem, games for mac anybody?!?
Stay cool... One day the DOW will be up again...
Regards
Morten Balling,
CPH-DK
Update: I've been playing some more and found a few a few interesting things. First of all: I Honestly think this will work once I get the 6 extra sticks that I've ordered. It's very important that all the sticks match each other speed vice. The final performance of the raid decreases a lot if only one stick is slow. Think of it as the classic thing with the chain and the weakest link. I benchmarked all the sticks I had separately and found a 8 GB Kingston that matched the two A-data i've got. Added that to the raid running OS X (new install needed). Strangely enough that helped a lot. There's a huge difference running on three sticks in stead of two. I've tried a lot of raids with harddrives and normally you have to have 2,4,8 etc to see an improvement (three HDD's gives the same performance as two but with a more steady performance across the drives once they get filled up). Running OS X on three sticks is perfectly doable, and I'm really looking forward to seeing what 8 similar sticks will do... From the testing I did yesterday it seems that the system is pretty scaleable, meaning that adding more sticks should mean equally better performance
A question: Does anybody know how the USB ports are routed to the USB busses? I have a 24" iMac7,1 Intel Core 2 Duo.
