Early 2009 Pro - Raid 0 without a card?

Discussion in 'Mac Pro' started by zepharus, Aug 1, 2009.

  1. zepharus macrumors 6502a

    zepharus

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    #1
    Is it possible to do a Raid 0 setup on an early 2009 MP Quad without the addin card? Would it even be worth it?
     
  2. kellen macrumors 68020

    kellen

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    #2
    It will allow you to do a raid 0 without the card.

    If you need the speed, it may be worth it. Just make sure to have a back up plan.

    Seen some people do a 3 disk array, with the 4th for backup. Do a quick search on this forum and it will pop up.

    Here ya go http://www.apple.com/macpro/features/storage.html
     
  3. Eisen Feuer macrumors newbie

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    #3
    I'm wondering this as well, unfortunately what drives I have to test the theory are PATA, not SATA...

    I know I've done RAID 0 before using disk utility on a stubborn dual drive enclosure that didn't RAID 0 in its own hardware, so I had to go the software route to make both drives one. So, I KNOW you can RAID 0/stripe two drives using Disk Utility. I don't see internal/external being an issue. The real issue is whether that drive reaped the speed benefits of being RAID 0, which I was too naive to test at that time.
     
  4. gugucom macrumors 68020

    gugucom

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    #4
    You will need a second SATA drive matching your system drive. It obviously would be best to buy two or three dedicated drives for the RAID0 array. The chipset on the MP can do RAID setups without any extra card in OS X and there is also a Intel software in Windows that does this for you. You cannot use the same array both in OS X and Windows. So remember when you want to stripe in multiple OSes you need dedicated drives per OS. Your Mac Pro has 5 SATA ports for RAID all together. The fifth is the one for the missing second OD drive.
     
  5. nanofrog macrumors G4

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    #5
    You could go up to 4 drives in a stripe, but as mentioned, you'd need a proper backup. That's easy enough, as you can stuff it in the empty optical bay. ;) You can boot off the array, so you aren't required to have a separate boot disk. Personally, I'd use the original drive in an external enclosure, and not use it as the basis of the array, as you're then locked into a specific drive (it may likely be too small as the primary backup).

    BTW, OS X's software RAID functions support 0/1/10. Any other type, and you have to use a hardware solution.
     
  6. zepharus thread starter macrumors 6502a

    zepharus

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    #6
    I was definately going to Use Raid 0. Is it a pretty fast solution? comparable to a Hardware add in card in speed?
     
  7. nanofrog macrumors G4

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    #7
    Assuming you're comparing the same drives and quantity in RAID 0 on both the sofware capability and a hardware solution, it's close enough. ;)

    On the hardware side, the cache may offer a small improvement, but not enough to justify the cost, unless you need additional drives (n drives) that exceed what the system can handle (available SATA ports).

    If you keep it to say 4 drives, you won't need to bother with hardware, as it would be a waste of money. :)

    Again though, I can't stress enough how important having a backup drive truly is. So hold off implementing the array if need be, as things really can and do go wrong. It's a better alternative to lost data at any rate. :D
     
  8. Mac Hammer Fan macrumors 6502

    Mac Hammer Fan

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    #8
    I bought a Mac Pro and the internal drive is a Western Digital Blue Caviar 640 GB (16 MB cache). I also have a Samsung Spinpoint 1 TB. I consider to build a RAID 0 with 2 drives without a raid card. Would I get a noticeable better performance with the Samsung Spinpoint (32 MB cache)?

    If the Western Digital is sufficient, I would buy this one.
     
  9. nanofrog macrumors G4

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    #9
    Do you mean to make a stripe out of the 640GB Blue and a Samsung, or two of the Samsungs? :confused:

    Assuming the latter, you'd get a nice boost (about 2x) that of one of them (or any set of identical drives). ;) Mixed sets gets a bit messy. :eek: :p It's doable though, and is almost always better than a single drive (comparing a 2 drive stripe to an SSD sort of tips the tables). ;)
     
  10. DoFoT9 macrumors P6

    DoFoT9

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    #10
    is a RAID0 always around 2x as fast? with both reading and writing large and small files?? or just sustained??

    i wonder if its possible to RAID a hackintosh dual boot system :p probably not lol
     
  11. nanofrog macrumors G4

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    #11
    It's typically based off sustained rates (published/available information), but logically, with all things being equal (identical drives striped vs. single drive operation), it's applicable to the other aspects as well. Random is a bit tricky, as though the random access time will decrease for an array, it doesn't divide by n drives. For example, you could find a drive in single drive operation obtains say 12ms or so, but the stripe could only get it down to 10ms, not 6ms. :p

    I don't see why not. You can always partition the drives first, and then setup a software RAID on one partition from each drive per OS. For keeping the worst case performace high, the partitions used for the arrays would need to remain at the 50% mark (capacity) in total. That wastes the inner tracks capacity, unless you have another use for them.

    So it might be better to use separate disks for each array to keep usable capacity higher. It also eliminates the need to use the boot camp partition tool, as that could be a PITA. :eek: The compromise of course, is the cost of additional drives. :p
     
  12. DoFoT9 macrumors P6

    DoFoT9

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    #12
    just wrote a nice big reply! but then my phone went flat as i was about to press submit.. great!

    i said something like::

    so for sequential writes/reads you can expect a nice improvement of near 2x, but for random it is diminished somewhat - this is because of seek times, finding available space and whatnot, or that is my understand of it anyway.


    oh you can RAID over partitions on seperate drives?

    soo..

    disk 1 has disk1s0 and disk1s1
    disk 2 has disk2s0 and disk2s1

    you can RAID (via software) disk1s0 and disk2s0 together, as well as disk1s1 and disk2s1 if you choose?

    i understand about keeping the discs empty for faster speeds and stuff, and creating your 'faster' partitions down low so they use the outside of the track (its outside right? too tired) etc.. but its good to learn more :) thanks!

    bed time now, nearly 11pm!
     
  13. seisend macrumors 6502a

    seisend

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    #13
    hey, just got my mac pro .

    I just installed the system now and did a RAID 0 out of three 1TB HD's. Does anybody know how I can partition my Macintosh HD (2.7GB=3x1TBHD's)

    I am in the Disk Utility programm and don't see how I can partion all of them, it doesn't display the partition option if I click on my main RAID0 array....


    EDIT:

    TESSELATOR, i am sure u can help me. ? need help :)
     
  14. Mac Hammer Fan macrumors 6502

    Mac Hammer Fan

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    #14
    You have to boot from a disk that isn't part of the RAID or from the macosx DVD
     
  15. seisend macrumors 6502a

    seisend

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    #15
    I booted my system with the Mac osx install DVD, I can't partition my RAID0 system there either when I start the Harddisc utility :(

    It is no option available.

    I can't continue installing my programms if my Macintosh HD isn't in several partitions.... So I am gonna wait until I got the answer .

    anyone ?
     
  16. gugucom macrumors 68020

    gugucom

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    #16
    It could well be that there is no option to partition RAID0 drives with that software facility. I tried to do this with two 64 GB SSDs and had the same result.

    Actually as Tesselator explained it makes little sense to partition RAID0 arrays because it is detrimental to their speed. So it may well be advantagous to analyse your partition demands and the available number of SATA ports. You can then decide your optimal strategy in terms of striped drives and partitioned drives.
     
  17. seisend macrumors 6502a

    seisend

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    #17
    Ok thanks for your reply. If partitioning the drives will decelerate the perfomance ( like you say Tesselator said :) ), I will install everything on my main HD.
    I just thought would be nice to have several partitions, but I don't want less the perfomance. Thank you !!
     
  18. nanofrog macrumors G4

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    #18
    Yes, you can do it, but remember, the drives must be partitioned first (definitely works in Windows and Linux). ;) And as I explained, it's not the best way to go. There can be more to it than getting into a situation where the entire array is on the inner tracks as well. Simultaneous access (of arrays on the same disks). But if you're using them for different OS's that are booted natively, that's not going to be a problem. ;)

    If you can, you'd be better off using separate drives for each array. :)
    You won't be able to partition the active boot drive IIRC. As mentioned, you'd need to boot off another drive, and partition that way, assuming OS X will allow this.

    Had you tried booting off a separate drive(s), such as the DVD media or a different HDD?

    I'd think it's possible to do it this way in OS X, but if it actually can't, it would be good to know. This does come up from time to time. :)

    As I explained to DoFoT9, it's better to use separate disks for each array, but it may not be physically or financially possible ATM, so I went ahead and explained "How-To" with at least an idea of the compromise/consequences.
     
  19. gugucom macrumors 68020

    gugucom

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    #19
    Thx, nanofrog! I had not followed that discussion. If you have to first partition and then stripe multiple RAID0 that could well be possible. I have not tested it that way around.

    It could also be quite different for SSDs than for HDDs because you do not have any geometric preferences. I would not be convinced that partitioning makes RAID0 arrays slower. IT may be possible but should be tested or explained properly before we transfer that bit of wisdom from HDDs to SSDs.
     
  20. nanofrog macrumors G4

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    #20
    If you're willing to test it, it could help others, as we'd have an absolute answer. :D

    As far as HDD's, I left it out. I guess simplicity didn't pay off this time. :p But it's possible, on HDD's as well, but for performance issues, capacity of all arrays mustn't exceed 50% of the total capacity (or each drive, which ever way one prefers to think. It works out the same). Wasteful, but necessary if additional drives can't be fit in the system.

    As for multiple arrays slowing things down, it's actually possible, but under a specific circumstance. Simultaneous access, where the arrays are being requested at the same time. The limit has to do with the capacity is attached to the same drive controller and that's connected to the same SATA port on the board. :p So long as this issue doesn't exist, or is very infrequent, it's not a problem. So the idea of splitting a set into multiple arrays for different OS's that are natively booted, it won't be an issue. :D
     
  21. DoFoT9 macrumors P6

    DoFoT9

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    #21
    first?? hmmmm... that would make it quite hard to do for OSX, also a PITA (to use your saying, very nice btw)

    and true, i couldnt possibly be running two OS's at the same time on the same computer!! so i think we are safe with the performance problem in that regard :p

    good idea! seems much more logical.

    correct, unless you are running the Bootcamp Assistant in OSX ;)


    here is the process i am thinking (theoretically):

    use OSX install disc, format the drives using the GUID partition table and split the drives into two partitions each, of a specified size. format one of the partitions on each drive as a Mac format of my choosing "osx extended". format the remaining two partitions as "free space". software RAID the two mac formatted partitions, then i get stuck.. is it possible to software RAID the "free space"?? im guessing so.. then use windows to install or linux or whatever blaablaa all done!! woohoo.

    hardware RAID would probably be easier, but more costly?

    for me yes, im poor!
     
  22. nanofrog macrumors G4

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    #22
    First in the sense of sharing drives for multiple OS's. Boot Camp would have to be run first, to create untied partitions. That is, without the partitions, it's all one large array under OS X. Even if you partition it later, it's still OS X based, and can't be read by Windows. :eek: ;)

    Shared drives with multiple OS's is the impression you gave me. ;) I did extrapolate a bit though, in thinking it was meant to be run natively, not VM'ed. :p

    Yes, Windows can use the "free space", so long as it's a partition. ;) You'll want to format it after, if it's not automatic (been awhile, so I can't remember if I had to do it manually).

    Definitely more expensive, though Fake RAID could work just fine for a stripe set, but I'm thinking you've enough ports yet you can just install extra drives for a separate array (perhaps later, as finances allows). :)

    Personally, I tend to have other needs that force hardware solutions. :rolleyes: :p

    Seemed the most likely explaination. :eek: :D :p
     
  23. DoFoT9 macrumors P6

    DoFoT9

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    #23
    windows wont be able to read it, but it could notice that it is there and then you could repartition it for a more "windows friendly" partition, right? or does the BootCamp Assistant create partitions in a different manner then what a normal partition utility will??

    yup yup no VM at all, just talking about using my hackintosh (with OSX + xp). :) you took the right road eheh


    you will need to format it again into a windows format (of course), it will see it but wont be able to do anything with it.. the question is, whether or not OSX can RAID two partitions of "free space" together.


    i haev a micro board, it has 4 sata ports, of which one is free. if i purchased a second 500GB WD HD similar to what i have now, i could partition it into two 500GB (or around that mark) partitions that are in RAID. would run nicely, i would want the performance on OSX though as i do video editing on it (sometimes). seem logical?

    not sure im following lol

    haha meany! a poor uni student i am!! give me a few years and, providing you are still on here, i will have the best of the best :p
     
  24. nanofrog macrumors G4

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    #24
    No, as each OS's implementation is different (not really just a result of the BC partition tool). Keep in mind, this all deals with the system level. So if you create an array under OS X, and are able to make some change to it using windows, the OS X sections would end up damaged (useless). :(

    Separating it via partitions before the creation of any arrays solves this issue. Windows at least can recognize free space per se, but you have to do something with it. Either continue to make additional partitions, format it, or create an array(s).

    I don't know for sure, but I'd expect OS X would want it formated first, but then you can set up the array. Like I said, I'm not sure here, but seem to remember having to do this in the past under Linux.

    Sorry, but I'm not following you here. :confused:

    If you mean to take a pair of identical drives and build a stripe set out of them, than yes, you'd certainly get a speed boost, which would benefit video/graphics work. But I think you'd want to run 3 or 4 drives though, given the comments made in the forum. (Figuring on 250MB/s or more, particularly with some discussions with Tesselator). ;)

    I was just commenting on my needs/resulting setup, and presumed you'd remembered. :p

    Two different cards, each running a RAID 5 array (one 4x SAS, the other 8x SATA).

    Who, me? :p

    Nah, I remember you posting you're in uni, which to me means "effectively broke after covering school expenses". :D Been there, done that. Oddly enough, I don't dislike Ramen noodles, despite how many packs I ate. :p

    Unfortunately, it won't end when you graduate, as you'll be paying the loans on top of normal living expenses. :eek: I'm assuming you'll be stuck with those things, of course. ;) :p
     
  25. DoFoT9 macrumors P6

    DoFoT9

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    #25
    haha sorry, ill explain more. i would wish to keep the same "dual boot" system i currently have, but have both of the partitions across multiple drives so that i see a nice increase in speeds.

    i refer to my scenario before..

    disk 1 = 500GB, disk1s0 = 250GB, disk1s1 = 250GB
    disk 2 = 500GB, disk2s0 = 250GB, disk2s1 = 250GB.

    if i combine disk1s0 and disk2s0 into a stripe, that would be a 500GB partition that has the advantage of being somewhat faster (if its on the right tracks). this would be my OSX disc. i would combine disk1s1 and disk2s1 to make another 500GB partition, the performance increase wouldnt be as significant as the OSX but still quite good. this would be for XP.

    making any sense lol?? what sort of increase should i expect? from 40MBps to 70mbps? 80? as is discussed, a 3or4 drive RAID is out of question atm. :( (to increase speeds i would find other areas such as higher overclocking and getting faster/more RAM - thats for another thread though).


    ahhhh yes i remember now.. well as much as i would LOVE to do that..... you know... $$$$$$


    of course you!

    haha! im into vegemite buns at the moment (not sure if yuu have heard of vegemite before, you would hate it). being poor sucks. i earn enough each week to get to uni, in the holidays i earn enough for my text books.. blah.

    great way to wreck my hopes and desires! my uni fees are going into what we call "HECS", (pronounced "hex"), its like a loan sort of.. we dont pay a cent for it until we start earning around $30k Aus per year, it comes out as a 2% tax... so you dont really notice it. so hopefully i can afford a nice server farm a few short years after i finish eheh.
     

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