Help with a RAID solution

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

  1. carlosparamio macrumors newbie

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    Aug 2, 2009
    #1
    Hi guys. After have reading tons of old messages on this forum, plus more external resources, I'm even more confused when I try to figure out a good hardware solution that solves my requirements. So I decided to write a new post hoping you might point me to the right direction.

    I currently have the following system:

    - Mac Pro 2008 (MacPro 3,1) 8-core 2,8 Ghz
    - 6 GB RAM
    - 1 Seagate ST3160827AS (160 GB) as the boot drive with OS X + Windows (via Bootcamp), connected to one extra SATA port of the MacPro and mounted under the optical drive.
    - 2 Western Digital WD20EADS (2 TB each one) to store my home, projects, etc, mounted in RAID-1 (mirror) by software
    - 2 Seagate ST31000340AS (1 TB each one) to store some more personal data, mounted in RAID-1 (mirror) by software

    I have around 2.5 TB of data already in use counting both RAIDs, so only around 500 GB separates me from be out of space. I work mainly with big RAW files and HD (1080p) video, so I expect that my requirements grow quickly with the time. So I want to move to a RAID solution that (1) gives me more disk space by adding external enclosures, (2) improves the performance of my system, (3) enables me to move from RAID-1 to RAID-5 or RAID-6 for the data volumes , plus have a separated volume for Time Machine.

    The idea is to have all my data on a same virtual volume, protected for 1 disk failure (RAID-5) or 2 disk failures (RAID-6). At the same time, have a second virtual volume to be used by Time Machine, just in case I end up with corrupted files or made a mistake and delete important files.

    At the beginning I was thinking to just mount a RAID-0 by software with 4x2TB units and acquire a Drobo or DroboPro, but it's an expensive solution, and it seems that the Drobo is really slow. Plus, I would like to have the backup option (via Carbon Copy Cloner or Time Machine) aditionally to the disk failure protection. I would prefer to add a RAID card to the system, use the internal SATA ports to mount the RAID-5/6 for my data, and use an external enclosure connected to the RAID card for Time Machine. Both for the data and Time Machine I would mount 4x2TB disks in RAID-5/6. How does that sound?

    However, I have some questions:

    - I can't decide which card is the most appropiate for me. I guess a RAID card with at least 1 internal Mini-SAS port + 1 Mini-SAS cable is required to mount the RAID-5/6 for my data. Will that connect the 6 internal SATA ports to the RAID card? I need to support at least 5 disks, 1 to boot OS X and Windows (it doesn't need to be part of the RAID, but I think it must be connected to one of the 4 bays in order to be used with Bootcamp; I will probably change the Seagate by one Velociraptor). Which card do you recommend me so I can build a RAID-5/6 with 4 drives, connected at bays 2, 3, 4 and the extra bay under the optical drive? Is possible to use the 5th disk under the optical drive as part of the RAID? I was looking at CalDigit, but the HD elements are really expensive, plus it seems that the data is saved across the disks in a strange format so in case the card was broken I would need to replace it for another one that was exactly the same (the same occurs with the Drobo). Also, it seems that it doesn't support the usage of the extra SATA ports on my Mac Pro 2008. Any other recommendation?

    - Are the Western Digital WD20EADS disks appropiate for the RAID-5/6? I've heard that it's better to use RAID class drives, but I really like the WD20EADS beacuse of the capacity, silence & price. Also, I already have 2 of them, so it would be easier for me to just buy two more to build the data volume.

    - Which enclosure would you recommend me to build my Time Machine volume which has low noise level, at least 4 bays, and (preferable) a similar look to the Mac Pro? I guess that the RAID card will need to have another external Mini-SAS port to connect to the enclosure. Is that right, or there are other connectors that could work / are better? Are the external Mini-SAS to Mini-SAS cables similar to the one that I need to connect the RAID card to the motherboard, or it's different? I've seen some towers at CineRAID. Maybe I'm wrong but it seems that they provide their own internal hardware to build the RAID, so I don't understand if that would work connected to the RAID card in any way, or if I would be paying more for something that can be made by the RAID card and should be looking for more basic enclosures.

    As you can see, I'm not habituated to hardware RAID solutions :) I hope that any of you could help me to see the light. Thanks in advance!
     
  2. Tesselator macrumors 601

    Tesselator

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    #2
    I'll let others answer which drives, which card, and which enclosures are best but what about buying two more 2TB drives, RAID0'ing them? Then add one or two more 1TB drives as a slower cheaper external drive set for a backup? You'll get the speed of RAID0 and you'll have your backup should even all four 2TB drives fail at once! :D

    So the setup would look like:

    4 internal 2TB drives as RAID0.
    4 external 1TB drives as RAID0 or just JBOD (concatenated).

    You'd need just the extra drives and a cheap-o SATA controller. This is cheaper than the other way, MUCH MUCH faster, and just as safe. :)
     
  3. carlosparamio thread starter macrumors newbie

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    #3
    That makes a lot of sense, and I was in fact thinking on doing something like that at the very begining. 4x2TB as RAID0 makes a super fast 8TB volume for data, which should be enough for some years (I hope!). But in that case, 4x1TB external drives wouldn't be enough for the backup after some time. Ideally, I would need other 4x2TB more, or even better, 5x2TB. Maybe a Drobo makes sense then for the backups, but because it is so slow, that made me think: "Now that I'm going to add a RAID card, why not buy one that enables me to add an external enclosure to put my backups that was much more faster than the Drobo?"

    What I don't want is to spend some money on a cheap, independent external solution when I could have a better & faster solution using the RAID card for a similar price.
     
  4. Tesselator macrumors 601

    Tesselator

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    #4
    I would hope so too! :D Unless 128-Bit 4,000 x 3,000 pixel frame cameras suddenly became the standard low-end. :p



    A question and a rule of thumb here:

    Q. Do you have more than 4TB to backup? I thought you mentioned 2.5TB as what you had.

    Rule: You ideally never want to fill a raid to much over 50% of it's total capacity - or performance begins to suffer. If you're amassing data that fast you need an alternate solution like a case of 1TB drives, some shelf space, and one of these: :D





    It wouldn't be a similar price though. An eSATA card is like under $100 and you can put them in a "software" RAID0. Pretty much any RAID card <$500 is going to be about the same speed (or in the case of the Apple RAID card, slower from what I've read). It's not till we get into the really expensive cards with 1GB or more of cache that performance is at all increased.



    .
     
  5. gugucom macrumors 68020

    gugucom

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    #5
  6. nanofrog macrumors G4

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    #6
    Tesselator's got a good idea, and it's inexpensive.

    The real issue for me, is getting a good idea of what you're expected capacity growth is.

    So long as you don't outpace the increase in drive capacity cycles, you'd be fine. (You backup the current primary array, install the new drives, make the stripe, and restore the data. Then place the "old/previous" primary drives in the enclosure for backup). Something like this would suffice, and it's inexpensive (it's a kit with everything needed, and it's Mac compatible). :D

    But if you need to change to a different array type or your capacity growth needs are faster than the frequency of larger capacity drives, you're going to have to go with a hardware solution.

    I'd need more details if the later is the case, but it's quite doable. :) Just not cheap initially, as the cards can get in the $1k neighborhood (slightly over actually, but they're 24 port models), and then there's cabling and enclosures as well. Enclosures and cabling can be added as needed, just as it is with drives, so long as you've ports available on the card. :) SAS cards can also allow you to use SAS expanders for massive drive quantities (Areca @ 128 drives, Atto @ 256 drives :eek:, but they're on the expensive side, and hopefully not even close to needed). :p

    Hope this helps. :)
     
  7. carlosparamio thread starter macrumors newbie

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    #7
    Tesselator, that's basically the solutions I've been using until now :)

    I bought one of the first SATA2 dock station (fall in love when I saw it):

    [​IMG]

    The problem is that it supports just one hard drive, it has a slowwwwwww USB 2 connection only, and it broke one of my hard drives after two days of use.

    A bit later, I bought this cheap box:

    [​IMG]

    The interface is also USB 2. I can put two disks there, and for a long time I had SuperDuper copying my files to separated drives on this box. The problem is that:

    1. It is slowwwwwwwww.
    2. The box just supports JBOD (not concatenated), so I had to separate my backups. Sometimes one folder was too big and complicated things.
    3. It makes just one copy of the files. I was dying to use an incremental backup system, and Time Machine sounds perfect for this. If I could have both disks as a single volume, at least I would use TM on them.

    I see that the dock station you suggest has an eSATA connector, which should improve the speed a lot. However, my backup copy is going to be > 3TB soon, and if I want to save some history, I would say I need a minimum of 4TB now, maybe around 5TB in a year. So I need an enclosure capable to store more disks, and put them in RAID (either hardware or software).

    I've seen some of your benchmarks using RAID-0 by software and taking advantages of the incorporated Intel chipset on the Mac Pro. It's pretty awesome. However, I wonder how much CPU needs software RAID to work. If I create two software RAID arrays (one for data and one for backup), the system will need to make more calculations when operating with both arrays (ex. copying files from one to another). That's why I firstly thinked on a cheap RAID card. I understand that the disk performance can be the same either on software RAID or a cheap RAID card in terms of MB/s, but I'm worried about the CPU.

    Nanofrog, the idea of the Sans Digital enclosure with eSATA interface looks pretty good. Would I be able to create a software RAID-0 with drives installed on it? There is a scary note at the specs of the card for this enclosure: "Please note that the host adapter card is based on Silicon Image chipset, which currently only support up to MAC OS 10.5.1 by Silicon Image".

    I will explain a little more my situation: I have 2.5 TB of data already. It grows ~0.75TB/year. I want to have an incremental backup system (Time Machine ideally) capable of doing the backups really fast, so I can execute them a couple of times per day (if I capture some video files from my HD camera, I want those to be protected on the backup as soon as possible). Alternatively, or additionally, if I'm able to make a RAID-5 instead of RAID-0 for the data array and/or the backup array, I would prefer that (it would be great that the whole system was super fast, but I'm more concern about reliability, so I can accept the difference in performance between RAID-0 and RAID-5), so if one disk on the data array breaks, I can continue working and replace the broken disk at any moment (leaving the backup as the last point of failure). This is preferable for me because to restore let's say 4TB on a new RAID-0 will take too much time from a slow backup device, and will force me to have an extra hard disk at home if I want to assure that I will be able to rebuild the array the same day it breaks.

    So basically, I think that a RAID card would be interesting because of the RAID-5 ability and because it frees the CPU. I don't need a super RAID card with tons of cache and a remarkable performance. I can live with a cheap card that does the job and ables me to connect the disks at the internal bays & ports together with some external disks at a enclosure, whichever interface it uses to connect them if it warranties a minimum of performance (mini-sas, eSata...). I know that it isn't recommended to mix internal & external disks on a RAID array, but because I will have 4x2TB internal disks, mounting them in RAID-5 will give me ~6.5-7TB, which should be enough for some years. And at a 5-bay enclosure, I could put 5x2TB disks for the backup array, giving me capacity to store the whole data array plus some more for the history.

    Do you know any card+enclosure combination that would able me to mount something like that?

    And a stupid question: Any RAID-5 configuration can restore a broken disk automatically once replaced, isn't it? If I want to add more disks to the array, would I need to recreate the entire array losing the data, right?

    Thanks a lot for your suggestions, guys!
     
  8. gugucom macrumors 68020

    gugucom

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    #8
    The version I posted has eSATA and two ports.
     
  9. Tesselator macrumors 601

    Tesselator

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    #9

    You can do that but I still wouldn't - unless I was backing up a single 3TB file or something. Just create three different schedule entries one for each of the 1TB drives. Also as I see the use for these cradle devices as Backup and Restore only. I would not leave it in place before or after the the BU/Restore. If they aren't hot-swapable an "Eject" will spin them down right?


    It's so little that it's not actually measurable. I guess less than 1/2% of a single core.


    I can try to isolate the process and monitor it in Xtools to come up with a specific value but I think even two RAID10s (4 total levels) in software are going to be less than 1% of one core.

    Anyone know the process names I need to look for?
     
  10. carlosparamio thread starter macrumors newbie

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    #10
    Yeah, I saw that. Pretty nice! But I still don't think this was an ideal solution for a permanent, incremental backup system with Time Machine.

    Thanks anyway! :)
     
  11. gugucom macrumors 68020

    gugucom

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    #11
    Sure, I use the thing exactly as Tesselator mentioned. :)
     
  12. Tesselator macrumors 601

    Tesselator

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    #12
    Well the way Carl wants has the advantage of faster backups which will be important for at least the first time you BU. Daily incrementals usually just take a few moments. Restoring (if that's ever needed) will be fast as well. 60 to 70 MB/s instead of 25 MB/s. (this is the average speed the OS and user home folders transfer at).

    If you go that way just make sure the card(s) supports X-RAID like "dynamic expansion" or else adding drives is going to be a major headache. Drobo and NetGear both have this for sure... I guess others do too. <shrug>

    Anyway, that's why it's configurable. Try it one way and if you hate it then try it another. It's all guud. :D
     
  13. joaoferro37 macrumors 6502

    joaoferro37

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    #13
    If you are wish to get the docking solution. You will have problem on the SATA connector. It will either break on the HDD end or the docking end.
    Getting a caldigit solution, then you are tied in with their hardware which is WAYYY over priced for the performance and quality. I've seen a lot of my clients sick and tired of caldigit's hardware and constantly phasing out products.
    I suggest using the High Point 4322 or Areca 1221x which are the real RAID card manufacture and get the JBOD enclosure from MacSales.com
    http://eshop.macsales.com/item/Raidon/ST66005SS2/
    or
    http://eshop.macsales.com/item/Raidon/ST8S2P/
    or getting the STARDOM DeckRAID DR4 which is a complete RAID 5 built-in solution with quad interface
    http://eshop.macsales.com/item/Raidon/DR4WBS2/
    Review of the product:
    http://barefeats.com/hard122.html
     
  14. nanofrog macrumors G4

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    #14
    You might want to think about a PM enclosure and an eSATA card. I found a complete kit available that might do the job (Mac compatible, but double check the version of OS X on Sans Digital's site), for $230USD. It holds 5 disks, and the PM chip is good up to 250MB/s (doable via RAID 0). :D

    The idea would work, just not sure about the specific card in the kit. You can always buy the parts separately. ;)
     
  15. joaoferro37 macrumors 6502

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    #15
    Mr. Frog, nothing against you, the card comes with it using SATARAID5 which is silicon image's solution. The RAID 5 and rebuild feature got problem.
     
  16. nanofrog macrumors G4

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    #16
    The post was meant to use it as an example (shows enclosure + card + cable) needed to accomplish it. I'm not familiar with the card, and am a tad leary of it when it mentioned on newegg ...up to Mac OS 10.5.1 ... ;)
     
  17. joaoferro37 macrumors 6502

    joaoferro37

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    #17
    Talking about DIY, I think the most important part is the RAID card and the power supply.
    Other than that are pretty standard.
    Of course getting a sleek enclosure will gain some degree of trust from clients that is why company like ProMax choose Stardom as their case manufacture and I believe G-Tech is using Stardom's enclosures as well.
     
  18. nanofrog macrumors G4

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    #18
    Most things have but a precious few manufacturers now, and everyone else uses one of them for their OEM/ODM suppliers. :(
     
  19. Tesselator macrumors 601

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    #19
    Why? It's just a standard connector. What's to break? Could you explain a little more?
     
  20. joaoferro37 macrumors 6502

    joaoferro37

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    #20
    Factors:
    Hard drives spins at 7200+rpm.
    SATA Durability: 500 cycles connect (Molex) which is the best SATA connector in the market and I do not think these manufacture will use Molex.
    http://www.molex.com/molex/products...ype=s&filter=&fs=&channel=Products&Lang=en-US

    The weight of a hard drive is usually at 1.5lb
    http://www.hitachigst.com/tech/techlib.nsf/techdocs/30C3F554C477835B86257377006E61A0/$file/HGST_Deskstar_P7K500_DS_FINAL.pdf

    The HDD docking is simply not a reliable solution and the SATA connector simply cannot tolerate the weight if the drive is installed vertical without any support.

    Besides, take a look at these two pictures. After I saw this post from http://www.hv20.com/showthread.php?t=11810 and my testing, I really don't feel comfortable using HDD dock.
     

    Attached Files:

  21. Tesselator macrumors 601

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    #21
  22. joaoferro37 macrumors 6502

    joaoferro37

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    #22
  23. Tesselator macrumors 601

    Tesselator

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    #23
    It's got a fan too:

    [​IMG]

    But it looks like you might have to mount the HDD inside that plastic thing prior to connection. Not really sure but if so that would put a damper on the concept.
     
  24. carlosparamio thread starter macrumors newbie

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    #24
    As I commented previously, I also had a similar bad experiencewith my docking station. One of my Seagate disks died after using it on the dock for some hours (I was moving data to it through the slow USB 2.0 connection) splitted in two days. After that, I didn't trust on the docking station anymore. I can't see any mark on the dock caused by hot, but I can remember that any disk inserted on it increased its temperature quickly.

    Thank you a LOT for all your recommendations. I have now a better perspective of my alternatives. Will post whichever solution I end with, to feed the knowledge base :)
     
  25. carlosparamio thread starter macrumors newbie

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    #25
    joaoferro37, if I finally decide to go with the High Point or Areca RAID card plus enclosure, I've seen that both cards have Mini-SAS interfaces, but the enclosures has eSATA interfaces. Should I use some of this? (wow! $74 for a cable!):

    http://eshop.macsales.com/item/Highpoint Technologies/MS1MES/

    Plus, these cards only have external Mini-SAS interfaces, so for the internal disks, I suposse will need to use software RAID. If I go with the hardware solution, wouldn't be better one of these? Will I be able to connect the internal disks to the card using the iPass connector (mini-sas to mini-sas)?

    RocketRAID 2684
    http://eshop.macsales.com/item/Highpoint Technologies/RRAID2684/

    I think that the iPass cable is too short to reach this tiny card. I guess will need a longer cable.

    I have one big doubt about the use of the internal disks through a RAID card. Does that connect ALL the SATA interfaces on the Mac Pro to the RAID card? I mean, not only the SATA interfaces for the 4 drive bays, but also the extra SATA interfaces on the motherboard.

    Thanks!
     

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