Previous 1 2 Next 19 Replies Latest reply: Jun 4, 2012 8:05 AM by Grant Bennet-Alder
Michael Levin Level 2 Level 2 (175 points)

I need some advice on high-end hardware (worried about specs and stability - not price).  I need to get a Mac Pro Server; this is for work and I'd like the fastest solution possible for the system disk (for a number of reasons I don't want to split it so that system disk and files are on different volumes).  Is this

 

http://eshop.macsales.com/shop/SSD/PCIe/OWC/Mercury_Accelsior/RAID

 

     better that the SSDs that look like a hard drive and fit into a hard drive slot? Any down-sides to this type of product?  And are the SSDs from OWC better than the SSDs offered with the Mac on the Apple site?

    

     Also: I need the primary disk to be about 1.2-1.5 Tb.  The biggest SSDs are smaller than that.  Any problem with ganging two of them as a RAID? I will also have a (regular)  disk for nightly clone backup and a regular disk for Time Machine (so I don't need redundancy on the RAID I think?).

 

thanks in advance!

  • Kappy Level 10 Level 10 (247,520 points)

    OWC's SSDs are better than the ones sold by Apple. But as for the rest of your query I'd say that you would be better served by talking with the tech support people at OWC especially about their products.

     

    Generally speaking you can RAID any number of drives whether HDD or SSD. I'm uncertain as to why you need constrain yourself to a one volume solution when you can create a RAID of high speed hard drives that can provide pretty fast service almost comparable with an SSD.

  • The hatter Level 9 Level 9 (60,375 points)

    WD 10K VR 1TB $300 each, 200MB/sec each. 3-4 of those - rule #1 keep adequate free space.

     

    4 x 4TB Hitachi $400 each - gets good feedback reviews on MPG

     

    SSD setups with multiple PCIe SSD can get to 1TB

     

    www.macperformanceguide.com

     

    for whatever reason but I would get the system and library data separated - you get much better performance

  • Grant Bennet-Alder Level 9 Level 9 (51,925 points)

    (for a number of reasons I don't want to split it so that system disk and files are on different volumes).

    The single biggest performance payback on a Mac Pro (that is not compute-bound and has enough RAM) is to establish a Boot Drive -- with System, Library, Applications, and the hidden unix files on its own drive. That is the way I run my Server at home.

     

    This keeps Mac OS X Virtual Memory system from wrecking the performance of regular file access -- whether you have the User files on a RAID or not.

     

    Also, if you expect "near Hard Drive" performance, Gigabit Ethernet with jumbo frames is a must. That may mean you need a Gigabit Ethernet Switch (but not a Router, since most file transfers go direct and do not use the Router).

  • Michael Levin Level 2 Level 2 (175 points)

    > establish a Boot Drive -- with System, Library, Applications, and the hidden unix files on its own drive

     

        I understand, but how do I solve these 2 issues:

    1) some of my applications keep important databases in system folders (not in ~/Documents). I don't want to mess with links across disks to try to fool them into putting everything onto another drive.

    2) backups: when everything is on 1 disk, it's very easy to clone it (nightly) and have a complete system that can be moved to another computer or used in case something goes wrong. If I have stuff spread across 2 disks, how does backup work?

     

       Maybe I'm not understanding how one puts the Boot Drive separately from one's files. How do you do it?

     

    > "near Hard Drive" performance, Gigabit Ethernet with jumbo frames

     

       sorry, what will be near hard drive performance? Do you mean files obtained over internet? What are jumbo frames?  This machine will be at work and I don't have control over what Ethernet switch they use.

     

    thanks!

  • Michael Levin Level 2 Level 2 (175 points)

    What # RAID do you recommend?  And is there any down-side nowadays from having a RAID boot volume? For example in my current Mac Pro, a known problem is that it won't boot into Safe mode with a RAID system disk.

  • Grant Bennet-Alder Level 9 Level 9 (51,925 points)

    An Application that insists on keeping its database on the boot drive, and has no mechanism for assigning it to another drive is doomed to perform like cr@p forever. If there is no method built into the program, you can move its database manually by using Aliases or Symbolic Links.

     

    This article by Japamac disusses the virtues of Boot Drives:

     

    Make room for Performance: Moving the Home Folder

     

    This chatty article discusses the same issue from a different perspective:

     

    http://chris.pirillo.com/how-to-move-the-home-folder-in-os-x-and-why/

  • Grant Bennet-Alder Level 9 Level 9 (51,925 points)

    Server software is most often used to support a multitude of Macs connected by an Internal Network. If that is not the setup you are intending to use, please ignore my outburst about upgrading your local Network to Gigabit Ethernet.

  • Grant Bennet-Alder Level 9 Level 9 (51,925 points)

    2) backups: when everything is on 1 disk, it's very easy to clone it (nightly) and have a complete system that can be moved to another computer or used in case something goes wrong. If I have stuff spread across 2 disks, how does backup work?

    Mac OS X contains more that a quarter million files that do not change from day-to-day. There is no need to spend the time or space to copy that stuff off daily.

     

    For Mac OS X, you make a clone. Depending on your tolerance, this could be monthly or more often as you desire.

     

    Mac OS X can be restored from DVDs and brought up-to-date in about two hours, without losing anything. Or downloaded in about the same amount of time.

     

    -------

     

    For User files, you can use Time Machine to do hourly automatic backups, and weekly or daily clones of just the User data. This takes much less time and is more likely to get done.

     

    For cloning User data, use a trio of External drives and take the latest drive off-site weekly (or whatever your data-reconstruction threshold is), as soon as the backup is completed. If User data is sensitive, you will need to encrypt the drive to take it off site.

  • Michael Levin Level 2 Level 2 (175 points)

    > Mac OS X contains more that a quarter million files that do not change from day-to-day.

    > There is no need to spend the time or space to copy that stuff off daily.

    > For Mac OS X, you make a clone. Depending on your tolerance, this could be monthly or more often

     

       yes; I have SuperDuper! make an automated clone so that I have all my preferences and other setup stuff backed up.

     

    > For User files, you can use Time Machine to do hourly automatic backups,

    > and weekly or daily clones of just the User data. This takes much less time and is more likely to get done.

     

       yep, I have that also.

     

    > For cloning User data, use a trio of External drives and take the latest drive off-site weekly (or whatever

    > your data-reconstruction threshold is), as soon as the backup is completed. If User data is sensitive, you

    > will need to encrypt the drive to take it off site.

     

       I do that as well.

     

    If I have my user data backed up separately from my System, how easy is it to 'reconnect' them in a restore situation (given that the System disk will have apps that need to be linked to databases and such that live on the User data volume)? I've been keeping everything on 1 disk because then the clone is standalone - I can bring it to any computer and have the exact same system I work in, without having to reset preferences or reconnect apps to their data. How does this work when the system and data disks are separated?

  • The hatter Level 9 Level 9 (60,375 points)

    Moving the system to different computers, huh?

     

    That is unique.

     

    You could have the system on one drive on each computer and move the database too.

     

    You are not talking about removing drive sleds or are you?

     

    You can take non-system / you could have everything in an external box

     

    But having system and even your and especially your database index and master files should always not be on the same drive.

     

    System drive - OS and applications and whatever normally goes into System, Library etc (and not sub folders in Users)

    DB Index (SSD)

    DB Master and support DB

     

    You could put everything in a 4-drive enclosure, would not change or matter though I think it is easier to have the system on internal boot drive (240GB SSD, WD 10K 500GB $200 200MB/sec - so both are almost the same except the SSD is 1000:1 faster adn higher IO per second.

  • Grant Bennet-Alder Level 9 Level 9 (51,925 points)

    The idea behind modern Operating Systems is that most System stuff is Read-Only by design. This greatly simplifies the Paging scheme. So you will find that the only System files that have changed since Installation are in:

     

    /Library/Caches

    /Library/Preferences

    /Library/Managed Preferences

     

    Dozens of other System Directories, representing tens of Gigabytes and over a quarter million files could be set to Read-Only with no impact on daily operation.

     

    For User files, all the files you as a User have changed are in:

     

    /Users/your_name/

     

    This includes all the preferences you set on a User-by-User basis-- they are in:

     

    /Users/your_name/Library/Preferences

  • Michael Levin Level 2 Level 2 (175 points)

    > Moving the system to different computers, huh?  That is unique.

     

       is that really unusual? What I love about Macs is that you can boot many machines off of 1 disk.  My stuff is mission-critical. So if I come in one day and my computer is having a problem, I grab my external disk clone, walk over to another Intel Mac, boot off it, and I'm working on exactly the same system as I had when I left the night before (it does automatic clones at midnight). I didn't think that was so weird :-)

     

    > You could have the system on one drive on each computer and move the database too.

     

      I'm not sure I understand. If the OS is on disk 1, and the user data is on disk 2, then as long as I move them both, the links should work, right?

     

    > You are not talking about removing drive sleds or are you?

     

       no, the clone is external.

     

    > You can take non-system / you could have everything in an external box

    > But having system and even your and especially your database index and master files should

    > always not be on the same drive.

    > System drive - OS and applications and whatever normally goes into System, Library etc (and not

    > sub folders in Users)   DB Index (SSD)   DB Master and support DB

     

       sorry, I'm not following.  Right now I have my system and data on one drive. How do I move it (keeping my preferences, settings, etc.) to a separate disk - do I just move my home folder and re-point it?  And what is "DB Index (SSD)   DB Master and support DB"?

     

    thanks!

  • Michael Levin Level 2 Level 2 (175 points)

    Am I guaranteed that applications I installed do not write things to other directories outside of ~/ ?

  • The hatter Level 9 Level 9 (60,375 points)

    Database systems have been around for decades and isolation of and use of multiple drives.

     

    And with OS X going back to early 2003.

     

    Keep what you have as backup, use CCC to clone just /Users to another drive.

     

    Clone OS with /Users and any account sub folder, and keep each accounts ~/Library with the system - makes life easier and easy to test.

     

    The OS is always linked to the GUID number of the volume (and volume can be a disk or an array) and the array can even be moved to different SATA ports, even from internal to external as long as all the members of the array or volume are present.

     

    Yes, the installer can be "trusted."

     

    Every database has its index, and to improve performance the index was / is never on the same device to reduce any bottleneck and let the index stay hovering and the database searches to be performed separate and concurrently.

     

    If you can load an index into memory and page-fix it great, use a RAM Disk (virtual volume) so the index does not need to be read into memory even to speed up requests (we use to serve 100s of users that needed 2 second response time, not 20 seconds).

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