MacPro 1,1 eSata / RAID question

Discussion in 'Mac Pro' started by c23roo, May 4, 2011.

  1. c23roo macrumors regular

    Joined:
    May 29, 2004
    #1
    Think I'm going to try to set up a 2TB (or more) RAID 0 to house my unwieldy iPhoto library (rapidly approaching 800 MB at this point).

    Question for the group: I saw this on OWC: http://eshop.macsales.com/item/Newer Technology/MPQXES2/
    and I wonder if I could use that cable, and hook it up to an external device like:
    http://eshop.macsales.com/shop/firewire/1394/USB/EliteAL/PerformanceRAID
    and attain maximum speed/performance.

    Or does it make more sense (or cheaper) to purchase 2 internal drives and set them up similarly. Right now all 4 drives are being used, but I could bump two if it gets me better performance.

    I would like to speed up drive access for iPhoto and I can't afford SSDs that big at this time. Tired of the beach balls...

    Any advice?
    Thanks,
    c
     
  2. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #2
    This could work.

    Just understand, that if any disk dies in a RAID 0, all the data is gone. So you must run a proper backup system, no matter what your primary storage media is. But it's even more critical with a stripe set (RAID 0) due to the fact there's no redundancy.

    These are on the same Intel ICH controller (contains the SATA ports) as those used for the ODD_SATA ports (ICH contains a total of 6). So there's no speed difference between this method or the external method you're interested in using.

    So long as the photos are large, a stripe set will help (increases sequential file access = large files; random access = small files, it's useless to you - for that, an SSD is the best way to go or using a RAID 10 can help too <more helpful for large capacity needs due to the lower cost/GB of mechanical disks>).

    Now if you want to use more than 2 disks, or do end up going to SSD's, you'd be better off going to a 6.0Gb/s eSATA card.
    • Simple version (only has 2x ports and controlls 2x disks) is here.
    • The RAID version (which actually means Port Multiplier support, which runs up to 10 disks) is here.
     
  3. c23roo thread starter macrumors regular

    Joined:
    May 29, 2004
    #3
    Wow! Thanks that was very helpful.

    Forgive the noob questions...

    Would the 6.0 Gb/s eSATA cards you linked to give me faster read/write speeds than the cable setup I linked to? I believe the native speeds are 3 Gb/s, no?

    I run scheduled backups of my important libraries to external drives by FW and keep them separate - not as concerned about speed there, so I think I'll be OK with RAID 0 in a stripe set.
     
  4. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #4
    What really matters is the slowest link in the entire chain, which are the HDD's.

    Here's a quick rundown (real world throughputs for sequential access):
    • SATA 3.0Gb/s port = ~270 - 275MB/s
    • SATA 6.0Gb/s port = ~540 - 550MB/s
    • SSD (avg. of performance models; there are some that are faster) = ~250MB/s
    • HDD = ~100 - 110MB/s for more recent, large capacity drives
    So as you can see, it's the HDD's that will be your limitation. If you want more specifics on the HDD's you intend to use, check out reviews of the specific make and model number (gets you accurate per disk information).

    In the case of a stripe set, the sequential performance = n disks * throughput of a single disk (assuming all disks are the same). Random access unfortunately, won't really improve (some even see a reduction :eek:).

    Thus for a stripe set of 2 disks, you'd be able to get ~200 - 220MB/s out of it or so. Definitely faster than a single disk for sequential throughputs, but not enough to saturate a SATA 3.0Gb/s port.

    OK, that's fine.

    You might want to double check to make sure the schedule is sufficient though (can't hurt, and it's where I see a lot of backup systems fall short). Just a thought anyway. ;)
     
  5. c23roo thread starter macrumors regular

    Joined:
    May 29, 2004
    #5
    Thanks again.

    Another question: if I go with a stripe set of 2 x 1Tb in RAID0, is it possible to back that up to, say, an external 2Tb - clone it on a regular schedule? I have no experience with using drives in a RAID setup - am I mistaken in assuming I can just copy the data in RAID to a similar-sized HD?

    - c
     
  6. ashman70 macrumors 6502a

    Joined:
    Dec 20, 2010
    #6
    You could do that but then your going from a non redundant solution to another non redundant solution, the safer thing to do would be to put two 1TB drives in Raid 1 giving you 1TB of useable and redundant space to work with until you outgrow it, and you wouldn't need to necessarily back it up because it would be mirrored anyway.
     
  7. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #7
    NO. RAID IS NOT A BACKUP.

    I cannot stress this enough. Now let me explain.... In the case of a RAID 1, what you do is automatically duplicated on both disks, so if you accidentally delete a file, it's deleted on all members of the set, thus the file is GONE.

    A backup will allow you to recover the lost file. A backup can also allow you to recover lost data if both disks fail, and ideally, you keep an off site backup to take care of natural disasters such as fire, flood, ... that would destroy the entire system. You'll do well to remember that insurance covers hardware, not data recovery (whether it be homeowners or what you get when you buy a UPS or good surge suppressor).

    Now in the case of using a single disk as a backup for a stripe set, this is fine. A single disk is actually safer than a stripe set (which is n times more likely to fail than a single disk).
     
  8. ashman70 macrumors 6502a

    Joined:
    Dec 20, 2010
    #8

    I am quite well aware that RAID IS NOT A BACKUP, I never said it was nor did I suggest he not have a backup, nor was I talking about deleting files but drive failure, but thanks for pointing it out.
     
  9. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #9
    The above post gives the clear impression you meant the OP could run a RAID 1 without a backup (more importantly no distinguishment of the pros/cons to doing so), hence the post. ;)

    It's wonderful if you realize the difference, but it wasn't clear, and more importantly, it can't be assumed the OP knows this.

    Just a thought.
     
  10. ashman70 macrumors 6502a

    Joined:
    Dec 20, 2010
    #10
    I don't mean to get semantic, but 'wouldn't need to necessarily backup' is not the same as 'don't have to backup', at least not to me anyway.

    It was not my intention to give the impression that a backup was not necessary, if that's what you read then now you know, it was my mistake.
     
  11. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #11
    It's just that the way it's written, I suspect those on a budget would take the same intent I did to their own detriment.

    I've seen users without a backup or a proper one too many times (most of all with RAID), and if possible, I try to offer sufficient advice to prevent this. Lost time and data translate into money. Significantly so if there's lots of it, and the user cannot afford to lose it.

    Just a thought. ;)
     
  12. c23roo thread starter macrumors regular

    Joined:
    May 29, 2004
    #12
    To clarify - I am incredibly vigilant about backup files. I have a set of drives that I keep off site, as well as a set on site in a fire-proof safe (I will swap these back and forth). Had a near-miss experience a long time ago (fortunately a recent backup saved me a lot of time and misery). I have found that it's much easier to keep some of these on a regimented backup schedule rather than rely on remembering when to do so manually. However, that leaves them in (or next to) the system, vulnerable in case of fire or other disaster.

    So as my Photo Library is the data I can least afford to lose, I have multiple backups. I am going to need more than 1 Tb for the whole library soon, so I'm going to need to go to at least a 2 Tb drive. For speed, I can't afford that kind of storage in SSD, so I'm hoping a striped set of 2 x 1 Tb (RAID0) will get the job done. For backups I think I will grab a couple of 5400 rpm 2 Tb drives and swap them in and out for scheduled backups.

    So don't sweat the backup advice; I am well aware of the need. Sorry to have you folks worry about the possible confusion.
     
  13. ashman70 macrumors 6502a

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    Dec 20, 2010
    #13
    Point taken, just not sure why you would take the risk of doing RAID 0 over RAID 1 though.
     
  14. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #14
    I'm no fan of stripe sets, but there are instances it's an acceptable compromise.
    Some common areas/reasons this could be acceptable:
    1. Very low budget (i.e. hobbyist/enthusiast, not a professional earning a living with the system). Thus they usually have more time on their hands than money, so fixing a broken array isn't that costly (do expect them to have a backup system to restore data from).
    2. Low access rate (which reduces the wear and tear on drives). In this case, I still would never advise a professional to do this.
    3. Temp data that consists of large sequential files, and an SSD isn't an option (i.e. disks already lying around, as a small SSD works for this, including random access temp data a stripe set won't help with, is cheap these days - OWC sells a 40GB disk for $100USD).
    I've the impression the OP is a hobbyist/enthusiast user, not a professional, and given the first post, 1 & 2 are applicable.
     
  15. c23roo thread starter macrumors regular

    Joined:
    May 29, 2004
    #15
    I would say I do fall in the hobbyist/enthusiast category in terms of my computer usage. My wife does a lot of photography in her spare time (hence the 800 Gb photo library). In addition to that, I am a musician, though not good enough to be my 'day' job - and do a fair bit of writing/recording. I'm not using this machine to make a living.

    I don't consider us to be necessarily low budget - I'm certainly willing to shell out the cash for some performance improvement related to our use of programs like iPhoto, Aperture, Final Cut, ProTools, etc... I've not been enjoying the more frequent (it seems) beach balls when scrolling through iPhoto, so I was wondering what might help out.

    As I suspect the slow link in the chain to be hard drive access for the hundred-thousand-plus photo files, I'm wondering what the best way to achieve this would be. I'm upgrading RAM, and now wondering if there's a HD configuration that might be helpful in this regard. I can't afford several thousand dollars for a 1 Tb SSD.

    So I guess I'm asking if you folks think there's a better way. I am also cognizant that I will outgrow the current 1 Tb drive soon and will have to go bigger anyway.
     
  16. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #16
    There's a couple of things you can do.
    • Place the OS/applications on an SSD (don't go too big here).
    As per the photo libraries and such, it will all depend on the avg. file size. For example, if the photos are say 8MB per, then a stripe set would benefit you (stripe sets are good for improving the performance of sequential access = large files; not the case with random access though, which is moving very small files (something the size of a few KB)). So examining your file sizes is critical to set you in the right direction.

    Regardless of what you do for your primary storage, you will need to make sure you've a sufficient backup system in place. And this is even more critical with stripe sets, as all data is lost if a single disk dies, and the only way to get it back is off of a backup location. Ideally, you'd even want a 2nd location off-site (i.e. online backup service), which covers you in the event of "Act of God" sorts of things like fires, floods, ... = entire system was lost. Insurance would only cover the hardware, not lost data (i.e. they won't pay for data recovery services).
     

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