1x G-Raid mini with HW raid1 OR 2x G-tech mini with OSX SW Raid1

Discussion in 'Mac Accessories' started by Bukem, Apr 7, 2010.

  1. Bukem macrumors newbie

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    Feb 6, 2008
    #1
    Hi Guys,

    I am wondering what will give me the best performance... I can purchase a 5400rpm G-Raid mini and use it in Raid1 mode. It has an onboard oxford 936 raid solution. See: http://www.g-technology.com/products/g-raid-mini.cfm

    Alternatively, I can get two G-technology mini's and use OSX to do the Raid1. See: http://www.g-technology.com/products/g-drive-mini.cfm

    Both solutions would be hooked up with fw800. The external drives would be used for storing files. I would then use an intel x25M (or V) inside my Mac Mini for the OS and applications.

    I currently use 2x LaCie Little Disk 5400rpm with fw400 and have OSX do the software raid. Uncached R/W performance is 33MB/Sec and 15MB/Sec. The drive scores a total of 28.72 using the Xbench testsuite. My current mini is a 1.87Ghz with 3 gigs of ram. This will be replaced by a 2.27 with 4 gigs.

    I've never had a drive fail in a raid but wonder how this would look in both scenarios.

    Looking forward to reading some of your comments!

    Bukem
     
  2. nanofrog macrumors G4

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    May 6, 2008
    #2
    A hardware solution is better than a software one when dealing with RAID. That Oxford chip uses an ARM7 processor, and performs the work rather than using the system's resources.

    It would also work on other machines (so long as the filesystem used can be read/written by the OS on the system it's attached to at that moment, unlike a software RAID setup under Disk Utility = OS X only).
     
  3. Bukem thread starter macrumors newbie

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    #3
    I was just wondering if that's still the case. A hardware raid is still software running on a chip. With the mac processors getting faster and faster the on chip raid processor advantage might have become insignificant.

    If you do the raid in software you'd use two separate firewire disks. If one disk would go haywire then it would be an easy swap for another disk. So I see advantages here as well.

    Does anybody know wether OSX gives an automatic alert if a software raid array becomes degraded? Or do I need a utility to do this?

    Many thanks for all of your input.

    Best regards,

    Bukem
     
  4. nanofrog macrumors G4

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    #4
    It's still the case.

    Now from the point you're making, there's some truth there. It is software stored on ROM running on a dedicated processor. But it's more than presenting as low load on the system's CPU. This presents itself in two ways.

    1. It does matter for parity based arrays, which do eat clock cycles when compared to say a stripe set (level 0), not to mention software can't deal with the write hole issue associated with parity arrays. You need an NVRAM solution to deal with this issue.
    2. Redundancy

    Software implementations are typically filesystem based, not block level (which hardware is). It makes a difference in the recovery behavior. It gets into the how the recovery is done (block writes are synchronous in hardware, asynchronous in software). This means the software implementations are faster, but have limitations (i.e. failures can occur under conditions you wouldn't expect from the product advertisements on software solutions).

    Then there's the advantage of being able to transfer a hardware solution from one system to another, and they can work with mulitple OS's (so long as the drivers exist to allow the OS to interact with the card - has nothing to do with the RAID levels, save nested parity which is both the card's firmware + drivers to accomplish).

    Finally, you can achieve speeds not possible via software. You end up with bus limitations (i.e. ICH10R in the chipset). You can get around this with additional cards (still using software), but it's limited to certain levels if you want to retain some reliability (i.e. level 0+1 or 1+0, the latter being more reliable).

    As per OS X, it will let you know if the array's degraded, assuming there's nothing else wrong with the system (i.e. failed OS disk, if the array's separate).
     
  5. Eddyisgreat macrumors 601

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    Oct 24, 2007
    #5
    If you get the g-raid mini keep a current backup that you trust. Mine died after 4 months of light usage (as in 1/4th of the space utilized, the rest never written to) and it took g-tech a month of finger pointing to get me my drive back.
     
  6. Bukem thread starter macrumors newbie

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    Feb 6, 2008
    #6
    Thank you guys for your elaborate replies. I guess HW raid is the way forward.

    Regarding the G-Raid Mini, I'm indeed seriously considering buying this drive but have two concerns:

    1) What is the quality of these units? I see the point you're trying to make but also realize that it's often the guy with a troubled drive that replies and the guy who has no issues refrains from sharing his experience.

    2) I don't intend to ship back a broken drive to G-Technology provided I can do the swap and get it to rebuild. Can this be done?

    (I might not be able to reply until after the weekend)

    Best regards,

    Bukem
     
  7. nanofrog macrumors G4

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    #7
    1. Poor. They're consumer model HDD's, not enterprise units which are designed for RAID use (especially with hardware controllers).
    2. Yes.

    A proper hardware solution would depend on the specifics, and may not be the best option (especially based on budget).

    For example, the cheapest RAID card that you can boot from, is the ARC-1210 (4 port, using SATA connectors) = ~$300USD. Add in 2x enterprise disks (say 1TB units) @ ~$160 each. So you've a total of $620USD spent to build a 2 disk mirror using a true hardware solution.
     
  8. Bukem thread starter macrumors newbie

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    #8
    I get the impression that the fw800 is the limiting factor here and that a fast HD should be able to saturate the available bandwidth. In that scenario a hardware raid or software raid becomes irrelevant. Actually....it ads another piece of hardware that can break!

    I removed my software raid from my mac mini and plugged a single drive into my powerbook. Disk Utility was quick to notice that the array was degraded. As soon as I added the second drive it started to rebuild it automatically so provided I connect the degraded raid to another OSX computer I should be able to rebuild it anywhere.

    What should keep me from doing it in software?????? I can't help but feel this is the better option here (fw800). If you have SATA ports available then things change.
     
  9. nanofrog macrumors G4

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    #9
    Different versions can be a potential problem area (there could be minor changes you didn't think were there = incompatible), and different OS's are beyond a problem (flat out won't work). Hardware can be transferred to any system so long as the card has drivers for the OS/s used, and it can read the filesystem. If the OS is on the array (from a working system), the only possible serious issue that can arise is if you go from an EFI based system to a BIOS based unit (or vice versa). You would have to adjust the OS to account for the different hardware though (i.e. different cards and chips on the board mean different drivers).

    Software can't do this level of transferability.
     
  10. Bukem thread starter macrumors newbie

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    #10
    My powerbook is a G4 running leopard, the mac mini runs snow leopard. Different OS, no problem running the raid on either system. How's that?
     
  11. nanofrog macrumors G4

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    #11
    SL's just a refinement of Leopard, and would be much more likely to work (though there is the possiblity that they could bork it in an update 10.6.x). But say you try to place an non OS array under 10.7 or later, there's a much stronger chance it won't work. This could also be the case between earlier versions of OS X and SL as well.

    It's hard to tell, and is a gamble if you need to depend on moving it from system to system.

    Something to think about.
     
  12. Bukem thread starter macrumors newbie

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  13. nanofrog macrumors G4

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    #13
    :cool: NP. :)

    I'm not sure how important the ability to move the array from one system to another is to you, but the most recent questions give me the impression it's fairly so. If it's highly important (as in you need to depend on it), I wouldn't put too much faith in the ability to transfer software based arrays (you're too likely to get burnt at some point). There is a compromise associated with the low cost. Afterall, nothing's free. :p
     
  14. Bukem thread starter macrumors newbie

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    #14
    I have absolutely no need to transfer the array to another computer. I tried to move it because I wanted to know if it could be done, wether OSX would warn me that the array was degraded and if it would automatically rebuild adding back the second drive again. (Lesson 1: always test your backup / contingency plans)

    What is important to me is minimal hardware. The more hardware is introduced, the more that can breakdown. I believe a SW raid is less likely to breakdown than a HW raid. What also worries me is that if the HW raid controller goes bust I have no means to restore the array except for trying to purchase one on the 2nd hand market with the risk of it having different firmware.

    The small performance benefit of a HW raid over a SW raid to me is negligible. I worry more about future breakdown..

    I'm now contemplating getting a mini using the X25V (40gb value) as the boot drive and a software raid1 fw800 solution with 2 G-tech 2.5" drives + an airport extreme with a 2.5" USB drive for timemachine backup. I would rotate the TM backups between alternating disks (I have 3). The reason to do this using an airport extreme is to physically move the disks away from the mac mini so in a catastrophe there is a bigger chance either one will survive. I also contemplate storing one of the three available TM disks off site.

    I think that this should give me reasonable speed, good uptime and redundancy.
     
  15. nanofrog macrumors G4

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    #15
    OK, so it was more of a curiosity rather than need.

    As per RAID, ALWAYS test it before trusting your data to it, no matter the implementation so you know what to expect in the event of a failure (it can also let you know if it's inadequate for the requirements as well before it costs you data and time).

    Hardware is more reliable than software implementations. Seriously.

    Granted, I spend my time using proper hardware cards, not SoC (Solution on a Chip) via FW or USB interfaces (too slow for what I work with). But failures with either, are most commonly the drives. Software is second with software based systems (it can be the logic/main board's firmware in some cases if you've access - built-in functions in the ICH in the chipset).

    Enterprise drives are meant to be used with RAID, especially cards (and is effectively a necessesity with SAS based cards, as consumer models are unstable). They're more reliable than consumer units, and have better specifications (i.e. Unrecoverrable Bit Error is typically 1E14 for consumer drives, and 1E15 for enterprise units). There's also additional sensors to prevent things like physical crashes of the heads into the platter/s.

    You won't really need them to make it work though, given the solution you're looking at. But it's not a bad idea either. Up to you.

    Always make sure you've a proper backup solution, so you won't loose data. Simply put RAID /= backup. Period. That's the biggest mistake I see repeated over and over again.

    Overall, this doesn't sound bad to me.

    I just don't like the external aspect of the array in this case, as FW is easy enough to accidentally knock the connectors loose of the system. At least FW offers Hot Swap, unlike OS X's SATA drivers in the Client edition (it is in the Server ed., but at $500USD, it's not worth getting unless you need it for other reasons).

    So be sure you don't trip over/knock out the cables during an operation. :eek: :p
     
  16. Bukem thread starter macrumors newbie

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    #16
    I must say that you're quite knowledgeable on the subject.

    I can see you're not in favour of a SW solution, changing the focus to a HW solution (without it costing an arm and a leg..) how do you feel about this:

    http://www.CalDigit.com/CalDigit_VR/

    Perhaps you have an idea about which drives would be suitable?

    It appears that it's a slightly more advanced raid implementation than a G-Raid.

    Rgds,

    Bukem
     
  17. nanofrog macrumors G4

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    #17
    Avoid CalDigit like the proverbial plague, as well as Apple's card (total POS).

    You'd be best to stick with Areca or a Highpoint RR43xx model. If you're only going to use 2x mechanical drives (or up to 4x), you want to look at the Areca ARC-1210 (cheaper, and it even boots OS X if you flash the firmware). Set the pair of drives in the empty optical bay, and use standard SATA cables and a Y splitter to get power to them.

    As it's hardware, you can safely use it with a parity based array as well (RAID 5), so long as you run it with a battery at a minimum. You're much better off with a UPS, but ideally, both. Even if you skip parity (future), get the UPS. They're really a necessity with RAID rather than an option.
     
  18. Bukem thread starter macrumors newbie

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    Feb 6, 2008
    #18
    Unfortunately the new mini tower accepts PCI cards, I'm stuck with the old model mac mini which only has a fw800 port to play with....:)
    I can understand that compared to a proper Areca solution Caldigit might lose the stakes but is it really that bad??
     
  19. nanofrog macrumors G4

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    #19
    Then you don't have a choice in the matter. The Mini was never meant to be used as a workstation, and hasn't the ability to run true hardware solutions.

    USB and FW is all it's capable of, unless you can stuff in a second drive internally and use Disk Utility to run a software implemented array of some type.
     
  20. Bukem thread starter macrumors newbie

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    #20
    There needs to be some kind of external storage system. I want an SSD drive as the boot volume so an FW800 (HW or SW raid) drive is the only option.

    I also want to separate documents and files from the OS.

    Again, does the Caldigit VR suffice here or are there better systems?
     
  21. nanofrog macrumors G4

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    #21
    I'd still stay away from CalDigit. They've a bad habit of bugs when released, and suddenly dropping support for their products (it's all ODM'ed, they design and manufacture nothing). It doesn't actually state if it's hardware or software based.

    Take a look at the Sans Digital TowerSTOR TS2CT (there's a 4 bay version too). They're not terribly expensive either (example).
     
  22. Bukem thread starter macrumors newbie

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    #22
    That Sans Digital link is fabulous !

    I'll have a look at their stuff, they seem to have plenty of choice. :)
     
  23. joaoferro37 macrumors 6502

    joaoferro37

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  24. mrj412 macrumors regular

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    #24
    I have the Sans Digital TS2CT and it is working very well with my Mini. It has two 1.5Gb Seagate drives and I have had zero issues with it. It is very well designed and is of high quality.
    I would recommend it without hesitation.
     
  25. nanofrog macrumors G4

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    #25
    I'm not sure if Sans Digital is the actual ODM, or if they're getting products from another company in Asia somewhere, but I've seen the same product with other names on it (multiple models, and multiple brands, such as Rosewill).
     

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