Better Throughput - Built-in SATA or PCI SATA Card?

Discussion in 'Mac Pro' started by jethrodesign, Oct 5, 2009.

  1. jethrodesign macrumors member

    Aug 6, 2009
    Hi, we have an older G5 1.6 Ghz tower that we are converting to a server. We will run our storage as a RAID 1 using two WD RE3 1TB drives, then probably put the OS on a separate smaller drive (possibly also on a RAID 1, not sure).

    So we will have to add to the 2 SATA ports that are on the MB. We are thinking about getting a Highpoint RocketRaid 1742 for this, so we would also get a couple external SATA ports for our backup drives.

    - So this being our setup, which provides faster theoretical throughput for the storage RAID 1 array - the internal SATA ports, or the SATA ports on the RR 1742 which are attached to the standard PCI slot (not PCI-X)?

    Thanks. Just trying to figure out which way to install the drives. We prefer maximum performance for the storage drive, as this is mostly all this server will be doing (serving files).

  2. Tesselator macrumors 601


    Jan 9, 2008
    If you're talking about Mac Pros from 2006 to 2008 then it's exactly the same. Exactly. No difference at all. The 2009 machines have a crippled embedded SATA bus so in that case the card's throughput will be the full bus bandwidth - whatever that is in the 2009 machines. I think 4 GB/s or something.
  3. jethrodesign thread starter macrumors member

    Aug 6, 2009
    Nope. Ancient G5 1.6 Ghz with a standard PCI bus (not PCI-X).

    I think the specs said the built-in SATA ports are at 150MB/s, but i read different things about the PCI throughput speed. Then there are different descriptions of speed as well (MB/s, Mb/s, max, sustained, etc.). Just looking for some knowledgeable clarification.
  4. Dr.Pants macrumors 65816


    Jan 8, 2009
    Internal SATA, IMO.

    SATA I operates at 150MB/s, wheras the PCI bus operates at a peak of 133 MB/s. Probably either will do fine, but going for OSX RAID 1 is probably the least PITA.

    Not to mention there's parallel vs. serial, which I'm not too hot on an explanation.
  5. nanofrog macrumors G4

    May 6, 2008
    The SATA ports on the logic board would make more sense for performance compared to PCI, ease of use and low cost. :D
  6. gugucom macrumors 68020


    May 21, 2009
    Munich, Germany
    I don't know about enterprise drives, but don't you get bigger drives by now?
  7. nanofrog macrumors G4

    May 6, 2008
    1TB's aren't a joke, but not the biggest either. The RE4 line is supposed to release a 7200RPM 2TB (WD2003FYYS), and it's late.

    What I don't get, is why jethrodesign hasn't sorted this out by now? :confused: He's posted this before, and gotten good information.

    What gives? An update would be appreciated. :)
  8. Tesselator macrumors 601


    Jan 9, 2008
    Umm, well, you need to make up your mind about a few things and look up the definitions of a few terms too.

    Bus Throughput which is what you asked about, has nothing to do with "sustained", "max", and etc. It's the total speed in GB/s that can be achieved over the SATA bus which happens to include 6 SATA ports (on the Mac Pro) total. It's a constant AFAIK so there is no max, sustained, or anything like that. Although this is supposed to be a theoretical value the tests I've see that set out to test it specifically yield very close to or exactly the manufacturer stated specifications.

    Then there's interface speed (notice it's not called "throughput" unless there is more than one connection or device) which on the Mac Pro (2006 ~ 2008) is IIRC, 375 MB/s. Nano knows, I keep forgetting this number. :D It's less than 380 and more than 350 tho. This is theoretical by definition but you get all of it in practice with all capable devices I've seen tested. The 2009 Mac Pros are crippled to something like 65 MB/s and the G5 you have is prehistorical so no written specifications exist. :D (j/k on that last bit... or not ;))

    Then there are the various speeds and throughputs of individual specific devices which vary GREATLY from device to device, from test to test, and even from data to data - as the actual data slash data-type being used in the test can greatly affect the results.​

    For Mac Pro 2006 ~ 2008 the throughput of the SATA bus (described in the first paragraph) is the same as PCIe throughput.

    As far was which is faster Mac Firmware RAID or a RAID Card; when all things are considered, they are exactly the same unless the card is a cacheing controller - and then for the sizeof the cache the card will be much faster. Cacheing controllers are very expensive AFAIK though. The combined cache of the drives used in a RAID configuration serve the same purpose as the cache on a cacheing controller. ;)

  9. jethrodesign thread starter macrumors member

    Aug 6, 2009
    Thanks for the replies. Yeah, I had a long thread a while back (before we got swamped), but at the end of it someone kind of threw a wrench into all the thinking by saying the PCI bus would throttle any advantages we were looking to get with a higher-end solution (like a true hardware RAID card, or external hardware RAID box). Maybe I could have posted there, but thought it might get lost in the shuffle.

    So for the sake of ease, we are just going with a RAID 1 with the two 1TB drives (which will be less than half full with all of our data). I think it's a safe bet for me to put these on the internal busses, and then I'll connect the boot drive to the Highpoint card (probably not using the Highpoint firmware setup if that's possible). I guess this would be the ultimate deciding point - if the computer can boot fine from a drive(s) connected to the Highpoint card.

    And I'll look into running SoftRAID which seems to be regarded much higher than the built-in RAID utility.

    Thanks for all the replies. I was just getting mixed information about the PCI bus speed (someone had suggested 33MB/s for standard PCI). But even if it's 133MB/s, then it's still 'theoretically' not as fast as the internal busses.
  10. nanofrog macrumors G4

    May 6, 2008
    For a RAID 1, then placing it on the logic board's SATA ports would be the best way to go all around (performance, ease of installation, and inexpensive).

    To use the Highpoint card as a boot device (OS drive), you must use it's firmware (EFI Byte Code, works for both 32 and 64bit firmware based systems).

    The PCI bus would operate at 133MB/s, but it's still slower than the SATA ports on the board. It's fine for a single mechanical SATA drive though. :)
  11. jethrodesign thread starter macrumors member

    Aug 6, 2009
    Great, thanks for the clarification! I ordered the drives & RAID card for $500. Should get them tomorrow.

    So to keep things safer and more simple, I'll probably run the boot drive as a standalone drive on the Highpoint RAID card (not in a RAID 1). This would probably make it easier to migrate in the future. And we almost never do much to the boot drive, so maybe an occasional clone using SuperDuper would suffice here.

    So for the storage drives, running just a simple RAID 1 with no partitions on the built-in SATA ports, would SoftRAID really give us any tangible advantages or benefits over the typical OSX RAID utility? If so, we're fine getting it. But if for something this basic it wouldn't really show, we'll probably save the $100+.

    Thanks again!
  12. nanofrog macrumors G4

    May 6, 2008
    I don't think you need to bother with SoftRaid at all, so save the funds. :)
  13. jethrodesign thread starter macrumors member

    Aug 6, 2009
    Well, since you fine people have been so helpful, one quick question while I'm setting everything up.

    - How long should it take for OSX Disk Utility to create a RAID 1 set with 2 brand new (completely empty) 1TB drives?

    I'm trying to setup the RAID right now, but it's been hanging on "Bringing RAID partitions online" for almost an hour now. Is this expected?

    Sorry, no documentation anywhere says anything about how long it should take. I was under the impression that since the drives were empty, it might go relatively quickly. Just not sure if I should 'force quit'.

    I didn't, however, create volumes on the new drives first. I just drug the drives into the RAID setup window where it seemed to give them arbitrary names. Not sure if this is causing an issue.

    THANKS! Almost there...
  14. jethrodesign thread starter macrumors member

    Aug 6, 2009
    Well, I ended up force quitting the RAID setup.

    But now I'm having another problem. I am unable to boot from the drive connected to the Highpoint controller. I though it worked once or twice when I first set it up, but then I installed an 'updated' driver from Highpoint and then ran into the problem with having to force Disk Utility to quit. I also had run Software Update and had installed a Javascript update, and a fairly large security update. Not sure which issue would have 'broken' the bootability.

    Upon restarting, I am unable to boot from the internal drive connected to the Highpoint card. I reset the PRAM, but nothing. Can anyone verify that this is definitely possible? I read something on Highpoint's website that it was only possible for Windows, Linux, etc. Not Mac. But I have no idea how old that comment was.
  15. nanofrog macrumors G4

    May 6, 2008
    It does take awhile. Exactly how long, will depend on the card, and I'm not familiar with that specific one.

    At this point, you'd need to start from scratch.

    Create the volume/s and initialize. Let it finish, then go from there.
  16. jethrodesign thread starter macrumors member

    Aug 6, 2009
    Well, I was trying the internal SATA ports for that.

    But I ended up switching everything around just to see if I could get it to work. So I put the boot drive on the internal SATA port (which works fine, so there must be some issue with booting over the RR SATA ports).

    And I put the 2 RAID drives on the RR 1742. I decided to run the Highpoint utility to initialize the RAID 1 just as a test. And after about 20-30 min., this was only at about 3% complete.

    - So should initializing a new RAID 1 on two completely empty drives (rather large ones, and a rather slow system) take seconds/minutes, or should it take minutes/hours when using the built-in SATA ports and Disk Utility?

    With the setup the way I have it, I ran XBench just to get an idea where it was. Here's the results. Let me know if this sounds reasonable for a 1TB RAID 1 on an older system, or if I should expect more. This is actually about the same as what we're getting with our current RAID 5, so we won't gain or lose:

    Disk Test 73.64
    Sequential 88.22
    Uncached Write 79.74 48.96 MB/sec [4K blocks]
    Uncached Write 81.64 46.19 MB/sec [256K blocks]
    Uncached Read 65.83 19.27 MB/sec [4K blocks]
    Uncached Read 186.61 93.79 MB/sec [256K blocks]

    Random 63.19
    Uncached Write 22.27 2.36 MB/sec [4K blocks]
    Uncached Write 138.57 44.36 MB/sec [256K blocks]
    Uncached Read 146.72 1.04 MB/sec [4K blocks]
    Uncached Read 228.90 42.47 MB/sec [256K blocks]
  17. jethrodesign thread starter macrumors member

    Aug 6, 2009
    Well, I just received a reply from Highpoint saying that it is not possible to boot from the RR1742 on a Mac, it's not recognized. So that kind of settles the issue for this whole thread, sorry. I wish that would have been more clear ahead of time.

    So last couple questions, I promise (well hope :rolleyes:)

    - I noticed in the HighPoint manager a way to enable NCQ for each drive (as well as Read Ahead and Write Cache, which were both enabled). Should NCQ be enabled for us? It is currently disabled.

    I didn't see any place in the HighPoint manager to set the RAID block size. Not sure what it's default is. I know when using DU, you have a lot of options, but the default is 32k. I was thinking we might do better with something higher as we are mostly serving files that are at least greater than 1MB, usually much larger. No database functions or similar.

    - Because of this, and possibly other factors, would I be better served to just have the RAID card see the drives as standalone (it calls them 'Legacy') and use Dick Utility to setup the RAID? Any pros/cons as far as reliability?

    THANKS!!! Hoping to get the whole switch done tonight, as our server has been crashing more frequently.
  18. nanofrog macrumors G4

    May 6, 2008
    Yeah, that can put a damper on things. :D :p

    You can enable NCQ if you wish. It can be a problem at times, and most card makers will default to "Disabled" as a result.

    I'd say test it both ways, and see what happens. If you get a little performance gain, and it's stable (issue you'd run into), then go for it.

    You won't. :eek: RAID 1 isn't a stripe set. The block size is the default of the OS. I know I can change this in Windows, but not sure if you could in OS X. But you could try to find it (I'd think in Disk Util somewhere). Otherwise, you'd have to change the array type to a level that uses stripes for it to show up. :p

    I'm not sure I'm following here.

    You want to set the drives to the card as Pass Through, and set up the RAID via OS X?

    I don't think this will help you.
    1. You still can't boot from it, as you're now giving me the impression you need this.
    2. Not sure how OS X would fare this way, as the RAID card could interfere with OS X's RAID functionality (I've not dealt with this model, so I'm unsure). You're describing HBA (non RAID) use, and control via software. It's possible, but an HBA is usually selected for such things. Z-RAID for more drives than the board is capable of for example. But most of the newer RAID cards will do this, and it includes those made by Areca, and it should include the RR43xx (Areca = ODM on this one). Atto as well (of cards that work on Mac).

    You could give it a shot if you don't need to boot off of it, but understand you're running an experiment to determine the stability and feasibility for your purpose. I'm hesitant to say it would work for certain, given the age of the design and the fact I've not used it to test this scenario myself.
  19. rtrt, Oct 9, 2009
    Last edited: Aug 13, 2011
  20. nanofrog macrumors G4

    May 6, 2008
    Disgusting! :eek: You're definitely evil... I like that. :D :p
  21. MacUserPeggy macrumors newbie

    Mar 17, 2009
    The RocketRAID1742 can't bootable, because the power mac G5 not support EFI. So I think you can put the OS on a separate smaller drive(internal PATA ports), and use RocketRAID1742 to create RAID 1 to storage your data. In this way you can make more performance and insure data security.
  22. MacUserPeggy macrumors newbie

    Mar 17, 2009
    The RocketRAID1742 can't bootable, because the power mac G5 not support EFI. So I think you can put the OS on a separate smaller drive(internal PATA ports), and use RocketRAID1742 to create RAID 1 to storage your data. In this way you can make more performance and insure data security.
  23. Tesselator macrumors 601


    Jan 9, 2008
    Minutes typically. I recently set up 15 or 20 different RAID configurations among 6 internal drives. RAID 1 initialization can take a while for sure - it's not instant!! But Disk Utility messes up and hangs 1 out of 6 to 8 times when initializing RAID sets so you might want to put a disk I/O indicator on it to keep an eye on things. If it takes longer than an hour or so it's probably stuck. When that happens just do what Nano says; reboot and start from scratch.
  24. jethrodesign thread starter macrumors member

    Aug 6, 2009
    Well, thanks everyone for all of the help!

    In the end, not originally knowing that the G5 couldn't boot over the RAID card, we had to put a smaller drive on the internal SATA port, and use the RR 1742 for our storage RAID 1, using two 1TB WD RE3 drives. We just used the Highpoint RAID Manager application to build the RAID. Seems simple enough.

    So it's up and seems to be running just fine so far. We don't really notice any performance increase over our older system, but that's OK. At least it hasn't crashed yet ;) . And I'm sure it's a more solid solution than our VERY aging G4!

    The only thing I've noticed, but not had enough time to look into yet, is that the fans on the G5 are constantly ramping up and back down ever few minutes. Not all the way up to the jet engine roar like some of the G5's, but enough to make you think it's working up a sweat. Doesn't last more than a few seconds, and doesn't seem to be tied to us doing anything on it (it happens when it's just sitting there dormant).

Share This Page