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Discussion in 'Mac Pro' started by Tonytownsend, Apr 20, 2010.
What are the advantages and disadvantages to have raid for a Computer only doing audio?
Which RAID (0, 1, 5) and how many tracks in what resolution and with what sample rate under what circumstances and for what purposes and with what software are you talking about?
Up to 35 tracks at most 44.1khz 24bit In Logic. I use a lot of samplers as well. Kontact,Guru,Symphonic orchestra. I was wonder which raid is best 0, 1, 5 doesnt matter, tryin to figure out what to buy with new mac pro
RAID does matter, as one does mirror (backup), one does stripe (speed) and one does both, and some more: http://en.wikipedia.org/wiki/RAID
So what are you aiming for?
Aiming for the fastest set I can get
I use RAID0 with 48KHz 24bit recordings and playback easily an Arrangement with 70 tracks with heavy synths aswell such as NI contents, Spectrasonics Atmosphere, etc. .. Reading and Writing is super fast.
RAID0 is the fastest you can get but not that secure. So you have to have a BACKUP ! If one HDD failes, all data is lost. I personally do not Backup all my stuff such as installations. Only my personal mac profile with all logic projects and librarys etc. are saved ! So if this will happen to me one day, I just have to install my programs again which will propably take one day but I have a clean system then anyway ;-)
You can use RAID 01 aswell, but you need a minimum of 4 drives:
RAID 0+1 (or 01) is a striped data set (RAID 0) which is then mirrored (RAID 1). A RAID 0+1 array requires a minimum of four drives: two to hold the striped data, plus another two to mirror the first pair."
I am also in the same situation as the OP and have been wondering about RAID with recording.
I was wondering however, do you run your samples off a separate HD with your Logic project files off another second separate HD? I have heard that reading and saving files onto the same HD will slow down Logic so I was thinking of keeping my sample libraries (I also use many NI stuff) on a mechanical HD, but I'm still unsure of where to store my Logic project files...
Oh and are you using SSDs in your RAID?
I have never heard of this slow down of Logic. Where did you read this (link) ?
I have all my samples/librarys/projects on my personal profile (intern HDD) stored (Macintosh HD/Users/my profile). The hole user profile is backed up. I have a 3x 1TB WD Caviar Black HDD RAID 0 installation and an external 1.5TB Backup at the moment. I never experienced a HDD overload in Logic and as I remember and the usage is always around 5% (I guess) anyway. I am not at home right now to look at it.
XBENCH RAID 0 Speed test (may not be the best program for this..):
Xbench Version 1.3
System Version 10.6.1 (10B504)
Physical RAM 12288 MB
Drive Type Macintosh HD
Disk Test 214.72
Uncached Write 347.02 213.07 MB/sec [4K blocks]
Uncached Write 448.72 253.89 MB/sec [256K blocks]
Uncached Read 82.55 24.16 MB/sec [4K blocks]
Uncached Read 559.92 281.41 MB/sec [256K blocks]
Uncached Write 101.31 10.72 MB/sec [4K blocks]
Uncached Write 787.11 251.98 MB/sec [256K blocks]
Uncached Read 271.09 1.92 MB/sec [4K blocks]
Uncached Read 292.63 54.30 MB/sec [256K blocks]
... I hope this helped.
You can't use RAID with Pro Tools, FYI. People have been known to have had problems and Digidesign has stated writing sessions to a RAID isn't supported.
Wow, thank you very much for your reply. It was very helpful.
Its just from a support article link I've read from Apple that I've read from:
After reading this, i just assumed that keeping your project files and audio & samples on separate HDs seemed like the most efficient way. But before I found this article, I wanted to keep both files on the same drive. And if you experience no hiccups, then I guess there isn't an issue at all really.
It appears the information provided by Apple is based on the presumption disks are used as individual drives, so RAID (no matter if hardware or software implemented), wasn't taken into consideration.
But RAID runs much faster. In the case of a stripe set (RAID 0), the throughput is n* single disk performance of the drives used. So a 4x drive stripe set is 4x faster than one of those drives by itself. So in such circumstances, you can put it all on the array, and not suffer throughput issues (but keep in mind, with mechanical disks, keep it at 50% full or less, or you're going to slow down on the inner tracks).
But as mentioned, make sure you've a proper backup in place. But with one difference: Backup is needed whether it's a single drive, or the most complicated RAID on the planet (and level implemented does NOT matter either, as RAID /= Backup).
Ah, thanks! I think I recall that Time Machine will backup the entire array as one drive, correct?
About the speed of the array, so you're saying a 2X drive stripe is 2x faster, 4x is 4x faster, etc...?
And what if your intended RAID is using SSDs. I plan on doing this, except my only concern is constantly writing to the SSD RAID. All those command+S, plus constant copying of samples and audio files into local project folders can't be good for the SSDs, can it?
Yes it will. So will other software, as it sees the array as a single disk (including the OS).
In the case of a stripe set, Yes. Throughput differs with other levels though (depends on n drives and the level of redundancy involved).
SSD's aren't the best for writes just yet as a result of existing Flash technology (especially MLC). The statistics used by SSD makers is a manipulation. They only utilize the best 90% of cells, and the wear leveling is based on an empty disk, which boils down to non-real world conditions.
SLC is a bit better suited (1E5 writes rather than 1E4 of MLC = manufacturer ratings), but it's expensive.
And there's also no long term data based on real world conditions. That seems too untrustworthy IMO. This will change, but I expect it won't happen until a newer form of Flash actually hits the supply chain at a low enough cost it's readily adopted (i.e. FeRAM, which has a much higher write cycle life rating by the manufacturer)
For now, it's best to keep high write environments to mechanical drives. So SSD's are fine for boot/application drives, but keep the rest of it on mechanical if you're writing often (especially temp/scratch data).
So your intern HHDD with samples/librarys/project is not part of your RAID0 setup, or is it? If it is separate HD, what are you using your 3x RAID0 for? Sorry I'm a little confused
Thanks, I figured that was the most practical solution for SSDS still today. So I guess a possible (good?) alternative is to keep a RAID0 of SSDs for boot/application, like you said, and then perhaps a second array of mechanical drives for temp/scratch/write and audio library storage to maintain the read/write speed?
This is just going back to my concern about keeping Logic project files, in which a lot of writing will occur, and the audio files library, in which a lot of reading will occur, on the same "disk". Do you think a mechanical RAID0 would remedy this, or is this probably something I shouldn't worry about...?
Just trying to figure out the most efficient way to read and write from...
You can use either a single SSD or a stripe set. I like the idea of the latter, but you have to be careful of the throughputs during simultaneous access (SSD + HDD raids at the same time), as you could throttle (exceed what the SATA controller is capable of handling). There is a limit within the chipset of ~660MB/s.
Lets assume a stripe set of 2x SSD's would use fast models, capable of delivering 500MB/s. That leaves ~160MB/s for everything else. A 2x disk mechanical stripe set can generate 200MB/s or so, using decent 7200 RPM disks. You've exceeded the ICH's limit.
You can get around it, but it means a separate controller in order to take some of the load off of the ICH in the chipset, by moving the data across the PCIe interface.
At this point, you'd really want to run a proper RAID card if it's to run the SSD's to make sure it's capable of handling the bandwidth, and you'd need more than the least expensive out there if you decide to add more than 2x disks later. The ARC-1210 for example, is fine with 2x Intel 80GB G2 units, but not more than that, given the processor used on that particular card. The ARC-1680 series is capable of taking on far more, as it uses a much faster processor.
So you have to chose between:
1. Single SSD + mechanical array on the logic board
2. Deal with the throttling and keep it all on the logic board
3. Get a RAID card and solve the throughput issues for the added expense
If you go through the hassle of getting both an SSD and a mechanical array, I'd split things up. Place the libraries on the SSD (as it's read performance), and the writes to the mechanical array. BTW, for best performance on a mechanical set, keep your capacity usage to 50% or less, otherwise you end up on the inner tracks, and they'll slow you down (and it gets worse the fuller the drive).
You end up with the best of both worlds as you've already spent the funds, and is really the best way to leverage the technology for your benefit.
Just don't forget to make sure you've funds enough for a good backup solution, no matter what you do (internal, or external, make sure you've enough capacity to hold whatever files you need to hang onto).
Cool, I see what you're saying about the throttle limits of the SATA controller. A 2x SSD RAID is probably as far as I'll go for now. But if I care to expand later on, I'll be sure to consider the RAID cards you've mentioned. Great insight on the whole matter. My understanding of RAIDs deepens further
Looks like I'll take things one step at a time then and try to achieve one striped set first and I'll see where I (and my funds) can go from there.
If you do RAID 2 SSDs, let us know if you find any real world performance increase (compared to a single SSD). In bench tests you will find them, but I'm sceptical about real-world performance.
I don't know if RAID is really worth the hassle, but it is essential to have discrete drives for your separate functions. Along with a backup, of course.
My own setup is (and it's pretty standard for audio work):
Drive 1: Boot/apps
Drive 2: reading/writing audio (where project files are saved)
Drive 3: sample libraries
Drive 4: backup/time machine
Will do for sure. First things first though: still waiting on those new Mac Pros lol.
Nice setup. That's exactly as how I had intended to have mine setup, if I weren't going to have a RAID setup. Also, I will be replacing the Time Machine backup with a dedicated Windows drive (I have a Time Capsule for backup).
It would be nice if Apple does what a lot of people have been suggesting, and that is have an extra drive bay, or even sacrificing one 3.5" bay for 2x 2.5" bays for a total of 5 HD bays.
That question usually has a pretty simple answer: if you regularly have to handle mid-sized files (50-100mb) or larger, then RAID0 will be worth your efforts. If not, then you really have to think about your specific needs for performance.