RAID5 options for Mac pro

Discussion in 'Mac Pro' started by daffydowden, Nov 10, 2009.

  1. daffydowden macrumors newbie

    Joined:
    Oct 29, 2009
    #1
    Hi All,

    I've recently purchased a new mac pro 8 core machine, which I'm very happy with. It's only the base model, but my plan is to upgrade it over time - as and when the components I'd like become more affordable. Anyway, my second upgrade (after the airport card) is for a RAID solution, having had several hard drives fail on me previously. I'm keen to get one installed soonish, but I balked at the official Mac Pro Raid card, which hasn't received many good reviews either.

    I know other members on these forums seem to have had good results with RocketRAID 4310 (with a little modding) and I've read that this card is based on the Areca 1680 series, which costs almost £200 more over here, so what are the differences?

    Does anyone have any experience with the CalDigit card? Is it worth paying extra for this card?

    I wondered if anyone else has had any experience with any other cards - either HighPoint or other brands - around that price range, or cheaper :D, that offer RAID5 support?

    As you can tell I'm fairly new to RAID setups, my first dabble with them on my previous PC was a cheap XFX Revo 64, so apologies in advance if things don't seem clear to me right away.

    Many Thanks,
    Daf :p
     
  2. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #2
    Apple's Raid Pro card is a pile of junk.

    I have the ARC-1680ix12, and an ARC-1231ML. They're both longer than the CalDigit, but I only tried the ARC-1680ix12 in an '08 MP. The cable fit, but it was really a tight squeeze.

    The HighPoint card is cheaper for a reason. It's eliminated some features, but it varies, depending on the exact model in the 1680 series. Some have the ability to add cache for example (this one really affects the card's length).

    The Areca's have enough firmware capacity to contain multiple items, including a copy of the Partition Tables (I don't think the RR43xx's do). This is a major feature if you ever have a problem, as you can recover arrays otherwise unrecoverable. It's worth having IMO (saves time vs. starting over, and restoring data off backups).

    The RR43xx can only boot a single OS. So if you want to boot OS X, you'll lose the ability to boot Windows or Linux. Depending on your needs, this may be a deal-breaker. But you also have to add $90USD for the cable extension from Maxupgrades to the overall price.

    Other details would help, like drive count, boot requirements, OS requirements (non boot), array levels (other than type 5 that may be desired),...

    As per the CalDigit's, I'm not a big fan. UltraNEO* has one, and has had good luck with it. But it's not as fast as either the RR43xx or Areca, and more importantly, to use the external ports, you have to use CalDigit's HDElement enclosures. They will NOT work with anything else. The HighPoint and Areca's don't lock you into their products.

    Sorry if it seems confusing, but it gets detailed. :eek: :D
     
  3. sidewinder macrumors 68020

    sidewinder

    Joined:
    Dec 10, 2008
    Location:
    Northern California
    #3
    I would recommend avoiding RAID 5. You would be much better off with a RAID 10 solution. RAID 5 has too many issues to be used by the typical user.

    There is the write hole issue, performance during rebuild issue, slow write performance issue, and potential for total data loss during rebuild issue. Avoid RAID 5 if at all possible.

    S-
     
  4. alphaod macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    NYC
    #4
    As recommended by nanofrog to me, I have an Areca ARC-1212 with a backup battery which I highly recommend; this is a great card. Personally if I were to make the same choice again I would go for the ARC-1222 which offers 8 ports instead of 4 of the former. Both cards are exactly the same otherwise. And it's bootable.
     
  5. BHamilton macrumors newbie

    Joined:
    Nov 7, 2009
    Location:
    Canada
    #5
    nanofrog sounds like he knows his stuff. I've read enough of his posts to base a solid setup for my own use. Whilst I'm going with the HightPoint RocketRaid 4310, I have no grudge against the Areca's. Work paid for the Mac Pro, however, the RAID tweaks are out of pocket for me. So based on some solid input from the guys here, I decided to pass by the Apple card, and forgo the pricey (and unavailable at the moment) CalDigit.

    As nanofrog said, there are additional costs with the RR's. No battery and the requirement of the MaxConnect make one contemplate the cost overall. That said, the RR 4310 is only 250USD all in. Its hard to pass that up. If its a mistake, there are enough people interesting in that card to make it easy to pawn off.

    I'll be posting progess on my endeavour over the next couple days.
     
  6. slughead macrumors 68040

    slughead

    Joined:
    Apr 28, 2004
    #6
    I use a highpoint Rocketraid 2314 and have a RAID 5. It works extremely well even in 10.6

    If you do a lot of hotswapping it's annoying, but otherwise it's CHEAP and effective.

    It is not technically hardware RAID (most aren't), but on a mac pro you wont notice.
     
  7. sidewinder macrumors 68020

    sidewinder

    Joined:
    Dec 10, 2008
    Location:
    Northern California
    #7
    nanofrog,

    You continue to do a disservice to people here by not pointing out the serious pitfalls in using RAID 5.

    S-
     
  8. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #8
    If you want to explain your reasoning in detail, by all means. I've mentioned it before, and is available via a search.

    I would expect, and have posted, that users take the time to do the research on their own. I don't think that's too much to ask. If they have questions, they're welcome to ask.

    But the hardware I've posted on uses NVRAM solutions to the write hole issue. There's also plenty of information about the write hole, and in some cases, explains how the NVRAM even works.

    As mentioned before, it's a compromise solution to limited drive locations and capacity. 10 is a safer way to go, but not everyone's able to implement them with adequate drives to suit their needs for both performance and capacity, as it means more drives and in the case of an MP, external enclosures.

    Keep in mind, the batteries are almost always options. The Apple card is the only exception I can think of.

    Also, test the card for failures. That is, make them occur. Pull the power, pull drives,... to understand how it will behave if such an event actually happens before you trust any data to it. With any card, as they're each different (different interfaces, as do features, such as Partition Tables in firmware).

    Also, you'd need to get a UPS. The batteries aren't perfect, nor is a UPS. It's all about mitigating the failures as best as possible given the specific requirements.

    OK, you understand that it's not a true RAID card. I'd suggest getting out of RAID 5, as you're playing with fire in your case. No NVRAM solution to the write hole. This is why I don't ever suggest using software based level 5 arrays. Your data is screwed if the parity data is corrupt, and a rebuild occurs. You end up with corrupt files.
     
  9. daffydowden thread starter macrumors newbie

    Joined:
    Oct 29, 2009
    #9
    Thanks for all your help guys.

    Regarding Raid 5 vs Raid 10, this is going oust me as a beginner, but when I started my search I was looking for Raid 1+0, didn't find any, so assumed there were none at my price range. I didn't realise Raid 1+0 and 10 were the same thing... d'oh! :eek:

    At the moment, I'm leaning towards the Areca 1212, don't think I'll need more than the 4 internal drives for the time being, really I just want Raid for my 'important' data. I'm planning on using a separate Raptor drive (scavenged from my pc) for operating systems and applications. Could you tell me, with Raid 5, when a disk failed the array rebuilt itself on the fly and you could still use the OS (the array was vulnerable, but still usuable), is this the case with Raid 10?

    The ARC-1680ix12, and ARC-1231ML are a little bit out of my price range. The money saved from not needing a third party cable could go towards the backup battery instead.

    Does this seem sensible to people, given my budget?

    Thanks,
    Daf
     
  10. gugucom macrumors 68020

    gugucom

    Joined:
    May 21, 2009
    Location:
    Munich, Germany
    #10
    I have an Arc-1210 in my MP4,1 and after some initial disappointments (can't do bootcamp) I have come to like the card.


    I believe the 1212 is made for external storage, not internal.

    One important feature on the MP4,1 is the elimination of harnesses to the internal HDD SATA heads. They sit directly on the logic board now. It means you have to find a way to use the traces in the PCB to connect between your RAID card and the internal ports. That may be a PITA. For me it did not matter because I use the card to run a bunch of SSDs from the 2nd optical bay and I simply connect by SATA cables. When you have zeroed in on a card have nanofrog advise you how you may be able to connect. Its a bit over my head.
     
  11. sidewinder macrumors 68020

    sidewinder

    Joined:
    Dec 10, 2008
    Location:
    Northern California
    #11
    It appears nanofrog is the only person here that is credited with knowing anything about RAID. So all you folks go right ahead and use RAID 5 just like he recommends.

    I'm out of this thread.....

    S-
     
  12. alphaod macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    NYC
    #12
    Actually when nanofrog made his recommendation he did stress that RAID-5 was unsafe with the write hold issue and the best way was to avoid it. If I really wanted NVRAM, I would need a form of NVRAM to store it.

    Also most of the RAM uses in the RAID controllers these days utilize ECC, so writing erroneous parity code is less likely.

    Sorry if you feel no one is giving you credit, but the problem is you're not explaining your position. Yes we now know of the write hole issue, but why is that important? A lot of folks will want to know why. A RAID card is not cheap by any means and I'm sure everyone would appreciate a lot of feedback. :)

    I'm sure you meant RAID 0+1 which is different from RAID 10. Former is a mirror of stripes, while the latter is the a stripe of mirrors.

    This card is for internal use. There are no external ports except for a Ethernet jack that you can hook up to your network, so you can configure the card on a web browser. To use a on a Mac Pro Early 2009 model, you need the sledges that can be found on MaxUpgrades.com
     
  13. daffydowden thread starter macrumors newbie

    Joined:
    Oct 29, 2009
    #13
    I stand corrected. Raid 10, from what people have said and the brief research I've done from this thread, makes most sense to me.

    What are these sledges? Could you explain why these are necessary? I'm presuming you mean this product correct? Am i right in thinking that these are necessary for same reasons gugucom talks about, that the hard drives connect straight into the MB, and that these will bypass this and connect to the Raid card? Do all other cards require a solution like this or only the Areca?

    thanks all for your continued help!
    Daf
     
  14. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #14
    Generally, I'd recommend getting an additional 4 ports for future expansion. It's cheaper and easier (saves time) to just add drives than to have to swap them out each time you outgrow the capacity.

    There's already a couple of users who've run into this. Bought a 4 port card, and realized they've already grown in capacity to need the extra ports.

    As per the rebuild question, Yes. If a drive drops out, the array will continue to work in degraded mode. But it's best to get a new drive in as quickly as possible (assuming it's mechanical in nature, otherwise it could be cabling, or firmware). The reason is, there's always the possibility that another drive can fail during degraded mode. You even have a risk of a second drive failure during a rebuild. Both usually occur if you have multiple drives from the same batch, and there are problem/s consistent throughout the entire batch. It gets ugly. :(

    The 1680 series isn't inexpensive by most people's definition, but you get a lot for the $$$. The ARC-1231ML is also a good card, but one I don't typically mention, as it will NOT BOOT in EFI. You can run OS X via driver support, but that's it. It's a good card for Windows or Linux (boots these) though (even in a MP).

    • Get the battery
    • Get a UPS
    • Use Enterprise Drives

    RAID cards don't handle recovery the same way as an OS does, so there's differences in the recovery timings set in the drive's firmware. Check the card makers site for a Hardware Compatibility List (not all offer one, but Areca does), to see what drives will function with the card (it's not going to cover every drive made). But it will save you headaches if you get a drive on the list when starting from scratch. Drives matter, even the firmware revision on them. SAS cards btw (ARC-1212 = SAS card), are picky with drives, so don't assume a drive will work. Check the list first before buying drives (you will even want to keep a spare on hand). If possible, don't buy all the drives from the same place, as you don't want sequential serial numbers (drives from the same batch). If there's problems with a batch, all drives are affected.

    Test out the drives first (SMART and bad sectors), and check the firmware revisions (just in case you have to flash them to a version that will run with the card; more likely if the drives just released).

    And again, I'd recommend getting an 8 port card. Say the ARC-1222. You can always upgrade the card later, but it's not convenient to do so IMO.

    You had a bit of a tough time with it to begin with, when attempting BC on it.

    Glad you got it sorted. :)

    It's an internal 4 port SAS model. The ARC-1222 is the 8 port version of the family, and they're similar to the 1680 series.

    The ICH10R (4 port grouping) has to be dissabled as well to make it work. It seems that's a firmware setting that can't be accessed by the user or 3rd party cards. So the adapter from Maxupgrades would have to be used in the '09's in order to use 3rd party cards.

    Cabling isn't that bad. Pics really help in understanding what the differences between MiniSAS and MultiLane are, as is the internal vs. external versions are. Then pay attention to the specifications to both the card, existing cables (if any), and enclosures used.

    NVRAM = cache + battery in it's simplest form.

    The cache is usually ECC, but may not be in some entry level cards, so check the specs (not sure if any still do this). But the addition of Partition Tables in firmware is an extension per se. It can allow for the recovery of an array that is otherwise lost if that feature is missing. It's not absolute, but it can help. So not all cards are equal, even if they employ an NVRAM solution.

    Batteries are typically an option, but advisable to have. So is a decent UPS.

    Most have this. At least the cards mentioned. It helps, but it's only part of the equation.

    I've been hoping he'd give the details in the posts. RAID 5 does have the danger of the write hole, and should never be under-estimated. That's why I really don't like Fake RAID cards with support to create a level 5 array. They don't have an NVRAM solution of any kind, and don't bother to explain the risk to users. Not on the site, or in the manuals. On those cards, sidewinder is absolutely correct.

    NVRAM helps extensively, but nothing's absolute. It even gets into the details of whether or not a battery is used, and the type of UPS. In the end, each system is different, and the solution is a compromise. Just like any other form of RAID.

    Overall, you test the system out first (computer, card, drives, and even cabling). It will let you determine if the specifics are stable. If it has a write hole problem, it will surface if you test properly. Typically in power outage scenarios (i.e. pull the plug off the UPS, and the system during a write). If you use files larger than the cache, you get to see what a corrupted file does, as this is the major limit of an NVRAM solution. In those cases, you get to re-perform the work. Woo hoo. :rolleyes: :p

    Actually, it's meant for remote management (and connecting to a Network Time Protocol server for accurate time).

    The Web Util that pops up in your browser will work if you never connect the Ethernet port, as it's built into the firmware.
     
  15. alphaod macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    NYC
    #15
    Yes those. And yes all RAID cards with the exception of the Apple RAID card will require the sledge. That is if you want it mounted in the regular HDD slots.

    Basically what you're paying for a 4 aluminium mount kits, each with a built-in SATA port. When you slide the sledge in, the power connector of the sledge will connect to the power connector on the motherboard and power your HDD. Not connected to the motherboard remains the SATA/SAS connector on your HDD which you use to connect to the RAID card. Mind you the included cable is a miniSAS 4i SFF-8087 to 4x SAS/SATA connector, if the RAID card you buy uses regular SATA cables, you'll need to buy straight to right-angle cables. The ARC-1212/1222 uses the SFF-8087 connector.
     
  16. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #16
    SZ-MACPRO09-MS06 is the exact model to be used for all 4 HDD bays with an SFF-8087 port on the card. ;) The most expensive one, of course. :rolleyes: :p
     
  17. cmaier macrumors G3

    Joined:
    Jul 25, 2007
    Location:
    California
    #17
    I just wanted to pipe in to say this is a great, super helpful, thread.
     
  18. slughead macrumors 68040

    slughead

    Joined:
    Apr 28, 2004
    #18
    I know, you told me that like a year ago :)

    I've got a good power backup.
     
  19. slughead macrumors 68040

    slughead

    Joined:
    Apr 28, 2004
    #19
    I'm convinced he's doing it on purpose. He's actually some kind of supervillain that delights when peoples' data gets corrupted. He's just spent this 18 months on this forum waiting for the 1 in 50,000 chance one of our RAIDs is going to die, then BAM! It hasn't happened yet, but when it does, he'll laugh maniacally and move to another forum to start again.

    That's obviously the most likely explanation.
     
  20. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #20
    A year ago? How dare you expect me to remember something that long ago... :eek: :D :p

    Seriously, power backup or not, you can still get burnt. It requires more than a UPS to solve it (you can still get a power glitch, even with a UPS, and more so with consumer units; i.e. writing when a brown-out occurs), as the "mistake" occurs in the methodology of parity based arrays (how data's written/read). A single stinking bit going wrong is all that's required to screw you up. That's the reason for the NVRAM solution, and ideally, the addition of Partition Tables to the firmware as a backup copy.

    And power doesn't help with partial stripe writes either. That's NVRAM territory (but more in terms of performance, than the write hole).

    For a softaware only solution, you'd be better of with a 10 array or some ZFS implementation (Z-RAID/Z-RAID2), which you can't do with OS X or with the card you have. You'd need a separate machine for the latter (hint: ZFS pool via ATA over Ethernet).
     
  21. gugucom macrumors 68020

    gugucom

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    May 21, 2009
    Location:
    Munich, Germany
    #21
    [​IMG]
     
  22. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #23
    Fixed it so the image would display. :D
     
  23. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #24
    If you can manage to implement ZFS based systems on OS X (or Windows for that matter), then be my guest. ;) I'm sure many would love the ability to skip an expensive controller (for an inexpensive HBA when more than 4 drives are needed). Me included. :D

    But as that's not an option, and won't be, since Apple's dumped their attempt to make OS X ZFS compliant, we're all SOL. :eek: :p
     
  24. sidewinder macrumors 68020

    sidewinder

    Joined:
    Dec 10, 2008
    Location:
    Northern California
    #25
    Is that all you got out of the link?

    Read this:

    http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt

    S-
     

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