Poor mans SSD ;-)

Discussion in 'Mac Accessories' started by EdbBob, Oct 25, 2008.

  1. EdbBob macrumors member

    Joined:
    Oct 25, 2008
    #1
    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 :apple:! ;-)

    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 :rolleyes:

    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.
     
  2. brn2ski00 macrumors 68020

    brn2ski00

    Joined:
    Aug 16, 2007
    #2
    nuts dude! but very cool....

    how much would a 64GB SSD cost right now? are you really saving that much loot?
     
  3. EdbBob thread starter macrumors member

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    Oct 25, 2008
    #3
    They are still pretty expensive, and furthermore this system runs via usb on the iMac. Changing the HDD on an iMac seems like an expert job... But most of all it's just for fun :) That said it could be nice with a large usb hub with two usb busses/hosts and a firewire800 interface... Hoping to receive more sticks wednesday. Can't wait :)
     
  4. EdbBob thread starter macrumors member

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    Oct 25, 2008
    #4
    And I might by crazy, but...

    http://analogbit.com/node/4 :cool:

    And already now the system is running pretty smooth OS X on three sticks. About the same performance as the internal HDD due to the extremely fast response of the flash ram in the sticks. (Instant response when you click something!)

    The only problem (apart from limited life of the sticks) I've found is that most sticks have lousy performance writing 4K blocks, but benchmarks can't really tell how they perform in real life application. I'm running Activity monitor on a HDD system as well as the Flash Raid, and even on the HDD Disk Activity rarely goes above 5 MB/s. (Probably due to OS X's excellent caching)

    Finally I found out that Corsairs Voyager sticks wich seem rather fast has a 10 year warranty, and they promise that it litterally means: "you can write to them from now and continually for 10 years without a hickup". We'll just have to see about that, now, don't we? :D One of the primary features of SSD disks is that they normally fail during write and not during read like HDD. That could mean, that even though a stick is busted, you should still be able to read it... Nice! Another funny feature of the Flash Raid is that you can bring one of the sticks when you leave your mac giving almost 100% security. That gives memory "key" a hole new meaning...
     
  5. EdbBob thread starter macrumors member

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    Oct 25, 2008
    #5
    Today I tried switching the sticks I use for the raid randomly to different usb ports (aften ejecting it). At first the raid didn't show up. I could see the stick showing up red in Disk Utillity, but:

    After a restart my raid was alive and kicking, wich means that this baby is portable using only the sticks!!! :cool: A portable system disk (probably provided you have a similar Mac at the other end), but still pretty small and pretty cool feature if I dare say so...

    I also verified that my iMac7,1 has two separate USB busses each 480 Mb/s. I've so far been able to pull 50 MB/s from one bus only wich greatly raises my expectations when i receive more sticks (they're in the mail). If this thingy deliver close to 100 MB/s with an access time lower than 0,1 ms at around 250$ a find it a bit of a sensation :)

    Any comments anybody?

    Wanna bet it'll work? :D
     
  6. vorkorsigan macrumors member

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    Sep 6, 2008
    Location:
    Toronto
    #6
    Completely mad idea, I would never use it but very very cool. when are you building the Delorien time machine?
     
  7. WPB2 macrumors 6502a

    WPB2

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    #7
    Thats awesome, I wanna try it. Let us know how it turns out.

    Not much chatter on the subject here huh?
     
  8. EdbBob thread starter macrumors member

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    Oct 25, 2008
    #8
    Ok here's a screendump showing OS X running on three stick's copying a 4.3 GB folder from the desktop to a Firewire 800 disk. Check out the disk activity...

    Need more sticks...
     

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  9. WPB2 macrumors 6502a

    WPB2

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    #9
    ok, so is it as fast as my internal HDD 5400?
     
  10. EdbBob thread starter macrumors member

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    Oct 25, 2008
    #10
    Yep, but it's only three sticks... ;) Btw write performance is 25 MB/s

    8 sticks should speed it up, but im allready considering even more sticks to max it out to the limit of the two usb busses.

    What you can't see on the screendump is the finder reacts instantly when activated, and as you can see a heavy application like Nuke runs perfectly (Film compositing software)...
     
  11. brn2ski00 macrumors 68020

    brn2ski00

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    #11
    LOL, but in all seriousness - the idea is brilliant and I am curious to see if he will gain a nice speed bump with more sticks!
     
  12. brand macrumors 601

    brand

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    #12
    A single USB bus will support up to 127 devices. Given that, I highly doubt that you will be getting anywhere close to the maximum number of USB devices that the standard supports.
     
  13. EdbBob thread starter macrumors member

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    Oct 25, 2008
    #13
    I was more thinking 16x8 Gb = 128 GB Drive. 20 MB/s write is what A-data promises per stick, but I've found 8 MB/s per stick is more true in everyday applications (small and big blocks). But 16 x 8 MB/s should give a recent overhead towards reaching about 50 MB/s per USB Bus. That could in theory mean close to 100 MB/s rw, wich is my goal. Of course that depends on the other USB devices you have connected, but that's no different than any other use of the computer. Everything you do on a computer will slow it down, but the flash raid is snappy to regain it's speed once the USB busses are free again. :)
     
  14. WPB2 macrumors 6502a

    WPB2

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    #14
    I have 2 USB hubs, all I need is 8x8gb flash drives, and a software raid in OS-X?
     
  15. WPB2 macrumors 6502a

    WPB2

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    #15
    forgot, I will be trying this on a new MacBook 2.4 aluminum. It has 2usb ports, but I think it is only 1 bus, so max 480mbps right? What performance do you think I can expect from that setup?
     
  16. misterredman macrumors 6502a

    misterredman

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    #16
  17. EdbBob thread starter macrumors member

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    Oct 25, 2008
    #17
    Ok, to those who want to try it:

    Caution! You might wear down the usb sticks. You can't blame me, but I'm doing it myself...

    First enter as many USB Sticks as you can. Try to put them on different Usb Busses as described above :)

    1. Enter the Leopard DVD
    2. Click install OS X (like normal)
    3. Once you have restarted, in the top menu bar select Disk Utility and select one of the stick in the left panel. in the right window select Raid. Now drag as many usb sticks into the right window as you can, give the raid a name (TurboFlashRaidDeuxe or something) and accept. Close DiskUtil.
    4. Choose your raid as install disk (next screen), and of you go!

    It's that simple :cool: You can still go to System Preferences and those your old HDD wich is untouched...

    Regarding the MacBook etc. I think you have two busses as well. Open System Profiler to check (see above)

    Happy Raiding! Tell about your results!

    Morten

    Of topic: :D
     

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  18. EdbBob thread starter macrumors member

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    #18
    Using only one Usb Port, the raid max out at about 50 MB/s RW (wich is sort of a world record for usb from what i can google) :) To have 50 MB/s write you'll either need fast sticks or many slow ones. Raid = Redundant Array of INEXPENSIVE Disks. That's the idea, Inexpensive rules!

    "A computer can never be cheap or fast enough" (some computer philospher once said)
     
  19. WPB2 macrumors 6502a

    WPB2

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    #19
    I bought 4 8gb geek squad USB drives, and was trying to striped raid, and got errors. I might need a walk through.
     
  20. EdbBob thread starter macrumors member

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    Oct 25, 2008
    #20
    As far as I can see your USB drives are U3 drives?!? From what I've read they have a small portion of the drive being read only. That could mean that if you drag the entire drive to the raid window in DiskUtil it cant erase the drive. Try to erase them first using Disk Utility. You could try to drag and drop the partition (listed directly beneath the disk). It Should look something like this:
     

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  21. EdbBob thread starter macrumors member

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    #21
    And after you hit create and confirm it should look like this:
     

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  22. MacsBestFriend macrumors 6502a

    MacsBestFriend

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    upstate ny (purgatory)
    #22
    Genius idea my man!

    I had an idea a few years ago when my and a friend were talking about a very basic OS on a couple of 1 GB USBs (back when they were 20 buck a pop). We thought that a company could take these and make a cheepo netbook that could be distributed to every student at school for a decent price (vs. teachers all using iBook G4's) I wish you had come around with this back then, and that there was a basic enough OS to support this (Verizon OS: texting, wi-fi, picture capability)!:D
     
  23. WPB2 macrumors 6502a

    WPB2

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    #23
    yes they are U3, but what is that gonna hurt. I am installing osx right now, and only have 6 min left. man it took like 1.5 hours
     
  24. WPB2 macrumors 6502a

    WPB2

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    #24
    Well I can certainly say it is slow as ****. I am running OS X Leopard, off 4-8gig sticks. I constainly see the beachball. I thought it was suppost to be fast. what am i doing wrong?
     
  25. ltldrummerboy macrumors 68000

    ltldrummerboy

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    Oct 15, 2007
    #25
    Genius. I should round up some of my flash drives and try this.
     

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