So can Time Capsule backup an 2 SSD Raid0 Array? And where does Windows go?

Discussion in 'Mac Pro' started by Icaras, Aug 3, 2009.

  1. Icaras macrumors 603

    Icaras

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    #1
    I've been scouring and trying to come to grips with RAID, as I've never set one up before. First things first however, and that is that I at least intend to purchase a Mac Pro and an Intel x25-m as a boot drive in the near future. Currently, I have a 1TB Time Capsule as my wireless backup solution.

    Considering this, say you had two SSDs in a software Raid 0, and considering this setup will yield any performance gains at all, would I be able to use the Time Capsule to backup the two SSD RAID array? How does this work? I know that Time Capsule can backup multiple drives, so is there really no complication in RAID and Time Capsule?

    Lastly, Windows 7. I've read somewhere here that the same array won't work with different OSes. So considering the first two SSD Raid 0 array is used for OS X, would I need a third hard drive to setup Windows, or would it be possible to partition one of the SSDs for Windows?

    Thanks to anyone who can clear this up....
     
  2. pprior macrumors 65816

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    #2
    A raid array appears to the os as a single drive, so you can backup normally.

    You can partition an array as desired, so you can put windows on a separate partition. There may be specific issues with windows and SSD (I don' do windows), so I can't comment on that.

    In general, raid-0 or raid-1 makes no difference to file useage/backup.

    I am curious however what application you use that requires raid-0 of SSD. SSD already is blisteringly fast.
     
  3. Icaras thread starter macrumors 603

    Icaras

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    #3
    Ha, you're right I know, which is why I am still really on the fence on the whole thing. I don't know, I guess I would just like to optimize performance further, if possible. But anyway I will be using my Mac Pro for audio work in Logic Pro and Ableton Live in particular. And if RAIDs benefit sustained read/writes, then an SSD Raid option at this point may also not be as appealing since I have over 200 gigs worth of samples and audio that I need to store. I'm only looking to get 80 gig sized SSDs at the moment and that probably won't cut it. Plus I probably wouldn't want to start diminishing the life of my SSDs with massive writing.

    That said, now that I think about it, it probably might be best to just have one SSD as the boot and application drive, and then have a secondary HDD for all my audio content.

    Anyway, I wonder if anyone here has benchmarked a Raid 0 of SSD?
     
  4. gugucom macrumors 68020

    gugucom

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    #4
    I have two Supertalent ME SSDs of 64 GB each as a RAID 0 boot drives in OS X. They run off the build in RAID controller in the chipset and are managed by the disk utility software. The primary reason for the RAID array was the size. I did not get fast 128 GB SSDs at a competitive price compared to two of them in 64 GB. So I decided to stripe them. I don't think it was a bad decision.

    For speed purposes it isn't such a good idea to partition RAID0 arrays. In my particular case I believe the software doesn't even allow that and I did not have the space to put my Windows partition on the OS X boot drive RAID anyway.

    So the only way for me to boot Windows is from a separate drive which is a HD in my case. I am considering to change that to SSD or an SSD RAID0 but at the time there are no real benefits for me. I use Windows only for Blu-Ray playback and occasional programs that are not compatible with OS X. I do not do any gaming.
     
  5. Icaras thread starter macrumors 603

    Icaras

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    #5
    I hadn't thought of striping two SSDs mainly to double your size at a cheaper price! Sounds like a good decision if you ask me :)

    Yea I intend to use Windows for nothing but gaming lol. I am not sure if RAID will help with Windows gaming at all, but having an SSD most surely should have an impact I would think.
     
  6. gugucom macrumors 68020

    gugucom

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    #6
    It truely depend if your disk I/O is a bottle neck to your gaming program. Usually it isn't if I understand the technology right. Your bottlenecks are typically GPU located. Every bit of GPU performace will typically give you better gaming. CPU and I/O isn't mission critical. But you gaming apps may load a bit snappier, I give you that.
     
  7. nanofrog macrumors G4

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    #7
    Think of it this way. When you stripe drives, you also reduce the aggregate random access speeds. They don't half (2 drive stripe), but it still ends up shorter than a single drive. :D

    Now consider the fact SSD's are the fastest random access drives on the planet, and a stripe would improve that. ;) You won't have a problem, as Abbleton needs good random access speeds as I understand it (I don't use audio software at all).

    As gugucom mentioned, building RAID 0 out of multiple SSD's will increase capacity, and save you some cash compared to a single large drive. You also get improved performance for the effort, so it seems a no brainer IMO. :D :p

    As for windows, it's hard to say (Boot Camp). You'd have to parition the drives first, and as they're to be shared, would think Boot Camp would be required. I don't know how well this would work, as you usually (windows, linux) partition the drives first, then create arrays out of the partitions (i.e. array 1 = disk0,partition0 + disk1,partition0, and so on). It should be possible, but ideally, you'd want to have separate drives for the different arrays. In the case of the capacity, that would be even more reason to do it this way. Also, by separating the arrays, Boot Camp isn't required, as they don't hold but a single OS. (You'd still have to run the disk in order to install the necessary drivers for Windows though, but not the partition tool).

    Another thing that should be noted, is partitioning the array will reduce the overal capacity of each array. This lower capacity not only affects the amount you can store, but it reduces the available unused capacity for wear leveling. This may not be an issue for you, but it could in very high write conditions. It all depends on the specifics, and I do think it needs mentioning, as that doesn't seem to get any attention by the drive literature or articles of late (it won't affect enthusiast users more than likely, but could in enterprise use). As I don't know the details on Abbleton's write behavior, I can't comment one way or the other.

    I hope this helps :), and hasn't confused you terribly, or worse, scared the crap out of you. :eek: :p
     
  8. gugucom macrumors 68020

    gugucom

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    #8
    Let us theoretically look at using three 80 GB SSDs since for each of the operating systems. 80 GB would be uncomfortably small for each. So depending of what you mainly use you would have to make a decision to use one RAID0 array and run the other OS off the single SSD.

    Now let us consider three single 80 GB SSDs where each drive is partitioned with GUID partion table. That means we start with three drives that have two partitions each. One invisible EFI partition and the rest in HFS+. Next we clone the OS X boot partition on all three drives. Then we start BootCamp on every one of those drives and make a 32 GB Bootcamp partition. When we have finished that we end up with the identical partition structure on all three drives. We will have the invisible EFI partition, one HFS+ of approximately 47,8 GB and a FAT32 partition of 32 GB.

    Next we boot into the Leopard disk and start disk utility. We create one HFS+ RAID0 array of 143,4 GB across the three SSDs and another FAT32 RAID0 array of 96 GB. The figures are just plugged out of the air. Adjust as you see fit for your needs. Of course all content on the SSDs will be deleted. Finally we clone the OS X boot drive content back on the big OS X RAID and install Windows in the other one . For performance in Windows we will eventually have to fit AHCI drivers to the Windows RAID0.

    I do not know if this is possible but it could be worth a trial. Both OS would run off a tripple striped RAID0 arrays. I do not know if partitioning will affect SSDs as negatively as HDDs because they have no physical sectors that run at lower speed. It is a straitforward solid state adressing system. There may be some latencies adding up, but that may be compensated by the striping.

    What do the experts think of such a strategy? We could have one additional 2 TB drive for data and one for backup. As data grow we could dedicate the backup drive also to data and switch to external backup.
     
  9. nanofrog macrumors G4

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    #9
    Overall, it looks good. Complicated, but that's how it would have to be given the use of Boot Camp.

    The only issue I can think of that might be a problem, is with the partition size for Windows. Installing Windows to one drive first (array is set up after Windows is installed) could be a problem. It would have to be shaved down as much as possible, so tossing the extras would be a good idea (if possible, depending on the exact copy of Windows used).

    Once the array is established, Windows would certianly fit. :D Albiet a tad small, but assuming its only an OS install (and perhaps some applications), not a problem.

    Which version of Windows are you using?
     
  10. gugucom macrumors 68020

    gugucom

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    #10
    Partitioning can be done without bootcamp but it would be a bigger risk. I would definitely use 64-Bit for performance and memory. So either Vista Business or Ultimate or Win7.


    I think that is a misunderstanding. I would first create the arry and then install Windows. I would not even go beyond partitioning because the formation of the array will erase everything. For OS X I would not be able to avoid fitting it because BootCamp will not work unless you have Leopard on the disk.
     
  11. nanofrog macrumors G4

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    #11
    I made the statement on the need for Boot Camp's partition table tool (understood this to be absolute), as some other comments (other members/threads) had led me to believe that it couldn't if the goal was to share the same drive(s) with multiple OS's (drives in the case of an array; anything the OS sees as a single logical drive).

    The issue with the Windows side and creating the array first (preferable IMO), is you can't access the firmware settings on a Mac (i.e. change the SATA settings to RAID). Those drivers need to be installed first before Window's software RAID settings can be used. So installing a copy on one of the partitions first would allow you to create the array, then you can go back and install it on the array (the creation of it is still there). :D

    Otherwise, doable. It's the lack of user control of the settings in the firmware that lends me to think it's not quite as easy. :confused:
     
  12. gugucom macrumors 68020

    gugucom

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    #12
    You can go around using the BootCamp assistent and end up with a perfectly working Windows installation on a multi partitioned drive. There are several ways. The easiest is installing the Paragon NTFS driver which lets you partition the Windows partitions directly in NTFS instead of FAT32. The advantage is reduced cloning of the OS X boot partition. All partitioning is done out of one OS X installation. The disadvantage is loosing the BootCamp program in Windows, which allows you to make some non vital adjustments. Sometimes that little Windows application will not be installed when you do not use the Bootcamp assistent for partitioning. I do not know why. It means you have to use the Alt key to select your boot system.



    I don't think that would necessarily be a problem. At that point the thinking is that EFI will see the Windows RAID array as an NTFS or FAT32 array made by OS X and will treat it that way. At that point you have two alternatives. You can install a fresh Windows from scratch. If you do it you end up with legacy drivers and there I understand your concern. Windows may not recognize the RAID array and malfunction on installation.

    One could also use a trick and install a Windows image from Winclone with AHCI drivers allready included. That could work. But I agree that it is all theory until someone tries and shows it can be done.
     
  13. nanofrog macrumors G4

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    #13
    I was thinking in terms of what comes with the system, so no 3rd party application to help make things easier.

    But the disadvantage you describe means the boot loader Windows places on the system isn't being installed, or if it is, it won't load. (Needed I would think if one would like to run say Vista and Win7 for example, as they're both NTFS). If it's just the one copy, you have the ability to hit the ALT key to select the OS of choice.

    I meant a new, fresh installation based on the presumption it would be attempted on a newly recieved machine, and it's the first copy of Windows ever to be installed (or similar situation).

    So no previous installs to help. Thus it seems the only solution is to make an intial install to one of the intended partitions, then create the array, and reinstall Windows to the new array. Drawn out (PITA), but it would work if there weren't any other installs, clones,... to speed up the process.

    This would work, but said resource would already have to be on hand. ;) Also, the clone, slipstream,... might have it's own difficulties associated with it, depending on the machine it was derived from (different drivers). So as I mentioned, I based the comments on the idea no such aids were available. :)

    It's an option though, assuming the resource is available. :cool:
     
  14. gugucom macrumors 68020

    gugucom

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    #14
    I'm in the middle of doing it. Will start a new thread with results.
     
  15. nanofrog macrumors G4

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    #15
    :cool: I look forward to the results. :D

    Good luck. :)
     

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