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Boot Drive - Single or 2-Drive RAID-0?

M

MitchLewis

macrumors member
Original poster
Jan 29, 2010
67
0
I'm still working out the details on purchasing a new MacPro. My Apple sales rep tells me that I can greatly increase the launch speed of applications and the system OS by purchasing 2 hard drives and using Disk Utility to stripe them together into a "software RAID". They claim it will be faster and more reliable than a single SSD.

I know I've asked this question before, but the answers were over my head. I don't know anything about SATA raid cards, or SSD's except for their benefits. But I'm pretty sure I can stripe two drives together and make a software RAID. The question is, whether it's a good idea. Reliable? Speed?

A friend told me that he remembered hearing that it was a bad idea to use two-drives for your boot disk. But he couldn't remember why.

Any advice would be appreciated. :)
 
I personally would put two HDDs in a hardware raid.

I've read a lot about SSDs having stuttering problems when used as the boot drive, and HDDs have faster write speeds. For me, I'll wait the couple extra seconds (if there is even that much of a difference) for the faster write speeds and better space/$.
 
MitchLewis said:
I'm still working out the details on purchasing a new MacPro. My Apple sales rep tells me that I can greatly increase the launch speed of applications and the system OS by purchasing 2 hard drives and using Disk Utility to stripe them together into a "software RAID". They claim it will be faster and more reliable than a single SSD.
Click to expand...
A 2 disk stripe set is faster than a single disk, but it is NOT more reliable (it's actually less reliable). It's cheap, and the performance gain for sustained throughputs is n drives faster than that of a single drive (so a 2 disk set is 2x faster and 2x the capacity of a single disk in the set).

That said, a single SSD is still faster if you get the right one (i.e. Intel's 80 or 160). And mechanical can't touch SSD for random access rates, which is what OS and applications really need. Mechanical can't come close in this regard.

By using an SSD as an OS/applications disk, most of the time you're only reading which is just fine (keeps the writes low - really only when you add a new application/OS update, and allows you to avoid the existing issues, as SSD's aren't yet supported by OS X).

Then put your working data (files you want to write) on mechanical, which is much better suited for a high write environment. You can use RAID here if you need throughputs in excess of what a single drive can do.
 
What are the advantages of a hardware raid? (verses software) The Apple tech said that because I was only using 2 drives, a software RAID would be fine and much easier to set up.

EDIT: I think I was typing at the same time as Nanofrog.
 
So I'm thinking that maybe I should just wait and go with a single hard drive for now. Then in a year or so, I can consider switching to a SSD.

We're all set with our external RAID storage (G-Tech eSpeed Pro), but I'm just trying to get more speed out of our boot drive without sacrificing reliability.

Nanofrog: You make a good point about not having to write to the boot drive much. But have a TON of applications to install (FCP Suite, Adobe Master Suite, Toast, Audio Software.....it goes on and on and on). Maybe I'd just be safer to stick with a standard hard drive for now? I wish I had more first hand experience with SSD's.
 
I see the Intel 160 sells for $499 on Amazon. I wish they made a 250 (we could use the room).

So am I to understand this correctly, the SSD is plug-in-play in a MacPro? Or will I need to do all kinds of hacks to get it to work? (sorry for the dumb questions)
 
RAID is faster.

I saw benchmarks a while ago that had two WD 2TB blacks in RAID 0, and they came close to a single SSD, but SSD's in RAID are insanely fast.

I have my boot drive as 2 x 1TB WD Blacks in RAID 0. It's a little quicker then the stock 640GB that came with the machine, but you HAVE to back up. That said, $200 now is cheaper then $1000 later for data recovery, so it's not a huge deal.
 
MitchLewis said:
What are the advantages of a hardware raid? (verses software) The Apple tech said that because I was only using 2 drives, a software RAID would be fine and much easier to set up.

EDIT: I think I was typing at the same time as Nanofrog.
Click to expand...
In general, a software RAID uses the system's resources to do the computations. In the case of an MP, doing so prevents you from running Boot Camp, and only works for OS X (no one's successfully gotten a software RAID on the logic board's SATA ports for Windows).

Nor can you easily transfer it from one machine to another.

As it happens, the ICH controller in the chipset can only run ~660MB/s or so, which is a real problem with SSD's and SSD + mechanical drives when run simultaneously. In such instances you wish to RAID SSD's, you need to use a hardware controller if you want to go beyond 2x drives (3+ will throttle). Combining SSD + mechanical (especially arrays) can also exceed the throughput limit of the ICH and throttle as well. (Hope you understand this).

If you plan to stick with OS X only, and won't run into an issue with throttling, then software RAID is likely going to be fine.

Hardware RAID controllers have their own processors and memory to do the work, freeing up the system to run applications. It's also faster (especially needed with SSD's in a RAID), easier to transfer from one system to another, and can allow for more options (i.e. RAID levels and more drives are big ones).

Beyond this, we'd need very specific details, such as software used, OS environment, boot requirements, throughput requirements,...
 
MitchLewis said:
Nanofrog: You make a good point about not having to write to the boot drive much. But have a TON of applications to install (FCP Suite, Adobe Master Suite, Toast, Audio Software.....it goes on and on and on). Maybe I'd just be safer to stick with a standard hard drive for now? I wish I had more first hand experience with SSD's.
Click to expand...
Applications are still mainly random reads, and where SSD would help. I can see capacity being an issue however, so think along those lines.

MitchLewis said:
So am I to understand this correctly, the SSD is plug-in-play in a MacPro? Or will I need to do all kinds of hacks to get it to work? (sorry for the dumb questions)
Click to expand...
There are larger SSD's available (there's a 1TB Colossus by OCZ - it's insanely expensive, but it exists). But there are 256GB models by other makers. Just put in the time to do the research to be sure the drive will be suitable for your needs.

There is nothing special to make them work either. They're SATA interfaces (indifferent to brand of the system).

rickvanr said:
I saw benchmarks a while ago that had two WD 2TB blacks in RAID 0, and they came close to a single SSD, but SSD's in RAID are insanely fast.
Click to expand...
It depends on the throughput desired. SSD's will beat mechanical in terms of Random Access, which is what you need for OS and applications.

Mechanical can be used to achieve high sustained throughputs (read and write), and for less money than SSD's (assuming there's no imbalance, such as a hardware RAID controller only used with mechanical drives).
 
rickvanr said:
RAID is faster.

I saw benchmarks a while ago that had two WD 2TB blacks in RAID 0, and they came close to a single SSD, but SSD's in RAID are insanely fast.
Click to expand...

We can't compare oranges to apples: in raw, sustained reads, a 3 or 4 RAID0 set of HDD will be faster than most single SSD. But that *in itself* is a huge endorsement of SSDs!!!

Also, a SSD as boot drive is head and shoulders above everything mechanical drives can provide, RAID0 or not. That's been established here in these fora and all over the web.

rickvanr said:
I have my boot drive as 2 x 1TB WD Blacks in RAID 0. It's a little quicker then the stock 640GB
Click to expand...

That's my point: nobody who's used one will ever say that a SSD as boot drive is *a little quicker* than the stock 640GB drive. It's ridiculously faster. As in night and day.

I went from a four disk RAID0 internal set as my boot volume to a SSD. The difference was significative. When I have to boot from a single HDD, the difference is simply ridiculous. Feels like using a computer that's trapped in molasses.

To the OP: don't hesitate to go the SSD way for your boot drive. You won't turn back. As I said: a SSD boot is noticeably faster than a FOUR drive RAID0. (As long, as nano said, that you use good SSDs. Intel's G2 for example.)

Also, using a SSD is the same thing as using a HD for all intents and purposes: just plug it in as you would a regular HD.

Good luck,

Loa
 
Thank you VERY much for the extremely informative replies.

Okay, so I think you guys have talked me into an SSD. I've been using my personal laptop as my main computer at work for a while now. It has a 185GB hard drive and I've installed all the software on to it that I'll ever need (plus my iTunes library and iPhoto library). So I think a 200GB SSD will be PLENTY For a boot drive....right? I could probably even get by with a 160GB.

So I see two 160GB Intel drives for sale on Amazon:

Intel 160 GB X25M Mainstream SATA II Solid State Drive (SSD) Retail Package SSDSAMH160G2R5 ($499)

Intel 160 GB X25M Mainstream SATA II MLC Solid State Drive (SSD) Bare/OEM Package SSDSA2MH160G2C1 ($465.99)


Another option is the Other World Computers:

256GB Crucial RealSSD C300 2.5-inch SATA 6GB/s 9.5mm SSD (MLC) 3 year Crucial Warranty ($794.99)

256GB Crucial M225 2.5" Serial-ATA 9.5mm SSD (MLC) 5 year Crucial Warranty ($697.99)

200GB Mercury Extreme RAID-Ready Enterprise Class SSD 2.5" Serial-ATA 9.5mm Solid State Drive. ($779.99)

So how do I do the research to find out which one is fastest, and potentially most reliable? Do I just go with the manufactures speed specs and warranty? (can't believe it's that simple)

Everyone seems to like the Intel G2 drives. Maybe I should just "keep it simple" and buy their 160 GB drive and be done with it.
 
I've been doing a little research. I found a number of "How To" articles on installing an SSD into a MacPro. They all suggest placing the SSD in the second optical drives empty space. But I'm planning to purchase a second optical drive, the SSD can't reside there. Can I just put the SSD in place of the original boot drive or one of the other hard drive slots?

I guess what I'm asking is if the correct wiring SATA connection and Power exists at all those locations.

Sorry, but frequently when I've tried to "blaze a new trail" things don't end up working out. :) I want to make sure this doesn't happen as this is my main work computer.
 
Doing more research. Just noticed there's a thread on here titled: "SSD Drives for Mac Pro Boot Drive?". Duh! It's long, but I've started reading it.

They point out that some of the drives wont work as boot drives because you can't install the OS on to them for some reason. (still researching....)

EDIT: Nevermind, the solution was to boot from the installation DVD, launch Disc Utility, format the SSD and then you can install the OS without issue.

This is starting to sound better and better all the time!
 
MitchLewis said:
I guess what I'm asking is if the correct wiring SATA connection and Power exists at all those locations.
Click to expand...
Yes, there's power at each drive location. In the case of the '09's, it's part of the port on the board or cable (optical bays, called a backplane connector = SFF-8482).
 
Don't know if you've made up your mind yet or not, but...

There's still such a huge premium on SSD drives, I'm not entirely sure it's worth the cost. Yes, you will boot faster, and your apps will load faster the first time, but once they've been loaded, the difference is so negligible as to be not worth mentioning. Given that most Mac Pro users sleep their computers, you could go a month without having to restart. Check this out if you have not already:

http://macperformanceguide.com/

He talks about SSD all over the place in his guides.

Personally, I feel your money is better placed in as much RAM as you can afford, and as much fast hard drive capacity as you can afford.

I have been using a three-drive software RAID-0 setup with three WD 500 Gig drives for three years now without a single issue. I use Time Machine on another drive I have in my 2nd optical bay. Every Sunday night, I make a FULL backup with SuperDuper to another 1 Gig internal drive, AND a data only backup to another external drive.

If you devise an appropriate backup and recovery plan, there's nothing to fear from a RAID-0 setup. The performance for cost ratio is worth the effort.
 
^^^^ Dude, you need to try an SSD. It will change your life! :D Without any hyperbole, it is the single biggest performance improvement you can make to your computer.
 
VirtualRain said:
^^^^ Dude, you need to try an SSD. It will change your life! :D Without any hyperbole, it is the single biggest performance improvement you can make to your computer.
Click to expand...

I plan to...once they no longer cost a monthly mortgage payment. :eek:
 
I can afford to buy one for my editing room computer. I am constantly launching huge programs throughout the day. For example my normal work flow is to:

Write the script using Word and or Adobe Acrobat
Record the narrator and and music using MOTU Digital Performer
Copy/Ingest the footage using Sony XDCAM Clip Browser
Log the footage using Sony XDCAM Transfer
Design any graphic elements using Photoshop and/or Illustrator
Edit the commercial using Adobe AfterEffects
Play the commercial in realtime using Final Cut Pro
Repurpose the video using Apple Compressor
Put it up on the web using Flash, Dreamweaver and Panic Transmit

In addition I'm using Apple Mail, Safari, Address Book and BusyCal throughout the day. That's 16 different applications! I'm hoping the SSD drive will be a godsend. :)
 
We've got a couple of external mini-SAS RAID's to use to store the data we create. I've been doing this for years and I understand storage/backup/etc... But I don't have any experience with SSD's.
 
MitchLewis said:
We've got a couple of external mini-SAS RAID's to use to store the data we create. I've been doing this for years and I understand storage/backup/etc... But I don't have any experience with SSD's.
Click to expand...
There's nothing special about backups with SSD's at all.
 
Okay, I think you're right. I'm going to pull the trigger and buy 160GH Intel G2 (Retail Box) along with the purchase of our new 8-core MacPro.

Thanks everyone for all the great advice! :)
 
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