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  • Best Hard Disc System

     Hi,

    I'm changing over to a MacPro in a couple of weeks and want to review my hard disc set up to maximise performance with Vienna Instruments/Ensemble. The MacPro is a 8 core 3.2 and will have 32GB of RAM.

    Currently for the VI samples I use 4 SATA drives in an external raid 0. The performance has been pretty solid with no problems and I think the CPU performance (it's a G5 2.5 Dual) was the limit rather than the disc streaming - though on a recent project I was extremely surprised to have 20 VI instances running without freezing!) I have seperate discs for audio, boot disc, etc.

    However I do remember CM saying RAID was not necessarily the way to go, rather spread the library across some discs. So what's the best way to go? and if I ended up splitting the library across say 3 or 4 drives (Strings/Brass/Wind/Rest) what happens if I have a very heavy Strings only arrangement - is this then slower than the samples streaming off a 4 disc raid?  I would want to avoid Raptor drives (elevated noise profile) and SCSI drives so would be either external or internal SATA-2.

    In addition if formatting the discs to a preferred sector size - what should this be?

    Thanks for any opinions

    Julian 


  • i received either from the 750 GB and from the 1 TB seagate (sATA II) drives 72 MB/s sustained read.

    so lets assume random read would be only the half then considering 256 voices need 22 MB/s you are very safe with actually 1disk

    (unfortunately i can't find my old EZSCSI tool which allows setting of blocks for random read)

    further considering you could use 2 internal disks for samples i wouldn't see any need for a raid ...

    makes sense? christian


    and remember: only a CRAY can run an endless loop in just three seconds.
  • Thanks Christian,

    Mind you if you consider the use of crossfade patches then each single line requires 8 voices (2 stereo samples per patch (4) with allowance for overlaps - total 8) So this would provide a max of 32 discrete continuous voices per 256 voice block - then there's the piano! So I guess data transfer could still be an issue. I do remember you saying you felt raid drives didn't play nicely with sample streaming - do you think this is still the case - for example would 2 or 3 J-Bods streaming samples fairly equally outstrip a 4 disc Raid 0.

    I had heard by the way that some people are having problems getting their MacPros to mount the 7200.11 Seagates (due to a firmware issue ?)

    thanks

    Julian 


  • Hi

    The main feature of Raid is increased bandwidth - but as CM points out there is usually enough throughput on modern disks

    to sustain many streams. However when it comes to stream-based sampling another factor comes into play because there

    is no continuous reading from the harddisk at all - its read operation to fill a samplebuffer is from a new location.

    In Raids the read heads in the disks are locked to the same operation as they have to read each their part of a data word syncronized *) - so

    they actually can't do much more random reads than a single disk (well, a little bit more since the datatransfer itself is faster)  - this is why 2 disks may be better because that doubles the random read capacity - provided that requests are evenly distributed btw. the 2 disks, eg a sensible distribution of most used library's.

    Accidently: CM, can you have the same library twice on one machine? If so the player and HD software should then have an intelligent

                     way to decide which set to stream from, eg. loadbalancing. 

    When it comes to sequencer tracks a Raid might be better because this is generally very long samples - not much random read and the possibility of read ahead operations.

    But maybe you should wait - 2008 seems to be the year when solid state (RAM) disks will have their break through

    Then you can forget about Raids and disk configurations. [:D] , Although they probably will be expensive at first.

    best

    Bjarne Kristiansen


  • Yes, I'm looking at SSD's for a boot drive. Expensive at the moment but it is projected prices will halve over the first few months - but still 128MB will likely remain the largest relatively affordable for a while. Julian

  • Relatively... price is relative indeed, you have to calculate the costs for every application. For instance, if you calculate for everyday server use the high initial costs of e.g. SSD may come down using the provided benefits. Yet for us sample player users the price/cost ratio of a normal harddrive is still a lot better, since we also need large capacities besides fast storage. Though I doubt you will outperform your 4-drive RAID-setup with your new computer... Btw. Raptors could be silenced fairyl well in watercooled housings if that's a concern.

    All the best,

    PolarBear 


  •  I agree currently SSD is not perhaps competitive enough at the moment to displace hard drives for large scale sample storage due to the size requirements.

    Where I think it has an early adopter role is as the boot drive. I've heard reprots of it booting a Mac Pro in 6 seconds along with massive increases in application launches. Some benchmarks show 5 fold speed increases over even a raptor on some processes.

    I think 128MB or 64MB at a squeeze  as a suitable capacity for a boot drive - also for noise freeks it's silent.

    Julian 


  •  Bench marks may only reveal one half. The other is usually never tested in benchmarks but commonly used. Just a warning not to believe everything that has numbers tagged. Rumour has it, that processors are developed just for a good benchmark result and not for perfect real world performance, because if the theoretical benchmark is looking good, the thing will sell like hot dogs. Therefore you also have to look at lifetime issues with SSD because in OS use it will most probably meet the MTBF rates, as well as the earlier generations selling for less money do have speed issues when writing to them. So the bootup may be fast, but in general use it might not be a siginficant speed boost, and then sonider the price again, at which a 30sec bootup comes. 6sec is far beyond anything that you would use, definately not with DAW software being loaded... just my opinion tho, until I have one of those suckers here I guess ;)

    All the best,

    PolarBear