Mac Pro: RAID 0 or JBOD?

[Renovatio]

I just received my two Seagate 750 drives for my Mac Pro today ... and while I wait another week to get the computer I wanted to ask for opinions on a RAID setup.

I am going to be using the system for heavy video and photo work and want to combine the two drives into one disk on the computer to make things easier to organise with a 160GB boot disk and 1.5TB scratch disk.

A friend recommended RAID 0 because of the huge speed increase in the disk read/write but from what I have read there are risks involved because if you lose one drive you may as well lose both.

So ... here is my question. Is RAID 0 worth the risk because of the speed increase or should I be safe and go with JBOD?

Chris

 

[kered22]

Well for comparisons sake barefeats ran a 3 disk and 4 disk RAID:
http://www.barefeats.com/quad07.html

The 4 disk write speed would be swell if everyone was running EIDE instead of SATA. LOL

I thought they ran a test with two 750GBs in a RAID, but they seems to have taken those results down. I can't recall if it ran at a good speed or really slowed down. You may want to try RAID just to see if Seagates has updated the firmware.

With the work you're going to be doing, I'd personally say to go with the RAID and keep a good backup regimine. The potential speed will really help out with productivity.

 

[syrianos]

i have 2x 250 gb disks as startup raid(striped), the speed increase is fenomenal, booting is so fast.
de second raid disk is a 120 gb and 160 gb disk i had from old systems, serial ata 150. (yes 2 different sizes)

but even then copying files from boot raid to second raid disk is a breeze, face it, if u use only one drive and it breaks you also lose your data, so if you use 2 and one breaks it stays the same, but u will have worked at high speeds. the mirror-raid just provides a secure solution for mechanical failures etc.

in the end it';s up to you, i have made my choice.

the only downside may be, i can't isntall bootcamp 1.1 because it says the startup disk needs to be one volume and not a combined one... i use parallels, but that doesn't support 3d rendering yet so games are out of the question.
still i hope the next update of bootcamp will let me allow to install to any drive, even if the startup is a raid.

 

[witness]

Why not add an extra drive and use raid 3 or 5 with a hardware controller. Then you get improved performance and it doesn't matter if a drive fails.

Hard drives are the probably the most unreliable part of a computer because they have moving parts but they are also the worst part to fail because you can loose data. If you have valuable data then you need a redundant solution or a good continuos backup solution.

 

[Sun Baked]

So ... here is my question. Is RAID 0 worth the risk because of the speed increase or should I be safe and go with JBOD?

Chris

I think you may find that there is no safety on the Mac with their scemes for making a big RAID 0 drive using either striping or concatenation.

With concatenation the files aren't lost, but the catalog recovery may be a PIA.

It is a software solution afterall still with all of HFS+ limitations.

Note: Many Linux distributions refer to JBOD as "linear mode" or "append mode." The Mac OS 10.4 implementation - called a "Concatenated Disk Set" - does NOT leave the user with any usable data on the remaining drives if one drive fails in a "Concatenated Disk Set," although the disks do have the write performance documented in the illustration above.

 

[Altimeter88]

Here is what I am doing when my MP gets here next week.

I will have the stock 250GB drive for XP MCE via Boot camp on one of the two extra SATA connectors mounted in the 2nd Optical bay.

For OSX I have 4 500Gb drives that I am going to run in RAID 10 (a stripe of mirrors giving me 1Gb of usable space). So that will be a RAID 1(mirror) setup for drives 1 and 2 and another RAID 1 setup for drives 3 and 4, then on top of that those two mirrors will be RAIDed in RAID 0 which will be seen in the OS as a single 1TB drive "supposedly" giving RAID 0 performance and RAID 1 security. Reading on the discussion forums at Apple.com this is kind of a pain to setup and you have to use a mix of the gui and command line to get it setup but I really want to see some performance benchmarks, I have a feeling that with Apples bs software RAID implimentatoin this RAID 10 setup will be slower than a single drive/non-raid setup.
It just sucks that Apple will not get thier act to gether and get hardware RAID up and running because the ports on the MB support RAID 0,1,5,and 10 nativly via the intel Southbridge. I would much rather just run RAID 5 so I don't have to lose half of my physical capcity nor do I want to run into potential problems where performance might suck with the software RAID, not to mention that BootCamp will not work if XP is partitioned on the software RAID setup.
I think it is a joke for apple to even offer software RAID as an option on such a high-end system as this is touted to be. No other server/high-end workstation would offer this as the only solution.
All my mid-range desktop PCs for the past 4 years have had hardware based RAID built into the Intel southbridge on the motherboard, I haven't even had to purchase a separate RAID card!!! C'mon apple fix this!!!
To be honest though I am quite excited to get this new Mac Pro, I am a PC to Mac switcher and have loved my MBP, I guess I just assumed that RAID would have been hardware based.

If anyone knows of any benchmarks with the various software RAID options on the Mac Pro, let me know. Also I will be happy to run some benchmarks with my RAID 10 setup if someone can point me to some good OSX hard drive benching software to use, I will post the results here for all to see.

 

[iMeowbot]

I think it is a joke for apple to even offer software RAID as an option on such a high-end system as this is touted to be. No other server/high-end workstation would offer this as the only solution.

The Apple solution is to use a Fibre Channel card and Xsan or Xserve RAID.

 

[Kunimodi]

I think it is a joke for apple to even offer software RAID as an option on such a high-end system as this is touted to be. No other server/high-end workstation would offer this as the only solution.
All my mid-range desktop PCs for the past 4 years have had hardware based RAID built into the Intel southbridge on the motherboard, I haven't even had to purchase a separate RAID card!!!

Actually, the builtin 0/1 (and occassionally 5) RAID that is in many non-server mother boards is software raid with a few cheap chips thrown in to barely speed things up; hardware raid is the kind that costs at least $100 for a card or is built into very high end PC server motherboards. Benchmarks in GNU/Linux show that the completely operating system provided RAID 0/1/5 is actually faster than most driver-supported, 'hardware' RAID that is built into desktop mobos. I would expect software RAID in OS X.

Truth be told, doing RAID 0 and 1 is quite trivial which is why (a) they do not need to be implemented in hardware and (b) they are cheaply implemented in hardware as mostly a marketing gimmick. If you're going to seriously do RAID 5 or 10, then you'd want a hardware raid card like these: http://www.newegg.com/Product/ProductList.asp?Submit=ENE&N=2000150410+1193812560&Subcategory=410&description=RAID&srchInDesc=

 

[macenforcer]

You know I find that barefeats test for boot drives flawed. I have setup 3 configs.


1. Standard 250gb boot
2. Dual 7200.9 500gb Seagates in Raid 0
3. Single 75gb WD Raptor 10K

The raptor is by far the fastest of the three but according to barefeats it is not. I can clearly tell a massive speed increase in launching apps and startup. Isnt that what really counts? File transfers I have not tested but ask me if I care?

 

[Altimeter88]

You know I find that barefeats test for boot drives flawed. I have setup 3 configs.


1. Standard 250gb boot
2. Dual 7200.9 500gb Seagates in Raid 0
3. Single 75gb WD Raptor 10K

The raptor is by far the fastest of the three but according to barefeats it is not. I can clearly tell a massive speed increase in launching apps and startup. Isn’t that what really counts? File transfers I have not tested but ask me if I care?

I have 2x74GB raptors in RAID 0 (my C: drive) and 3x300GB in RAID 5 for data storage in my current PC and have used the fastest 15Krpm drives and RAIDS 0,1,and 5 over the years in all of my PCs so I am familiar with the performance gains and what should be expected.
This being said, I don't understand the numbers either posted at barefeats. Now I am a new PC to Mac switcher (my MP gets here next week so I am not familiar with the bench utilities they are using etc. but the raptors in all other PC benchmarks I have seen are always faster in both access time (~8ms after overhead vs. ~12-17ms in 7200RPM drives) and avg. read/write transfer times.
Now larger 7200rpm drives (500Gb and 750GB) are closing the read/write gap because as platter density increases for a given speed, so does read/write data transfer times. This will not affect access time though, so the raptors will always be faster because they can access the data quicker. The raptors despite low platter data density are still faster than any 7200rpm drive that I have seen though, this is because of the 10Krpm speed again still giving it a slight edge in data transfer.

Now regarding RAID on the Mac and some of the comment above. Are you guys serious?!? "Apple does offer a nice solution for you average Joes buying your new Mac Pros and wanting to run RAID 5, it is called the xServeRAID +FibreChannel card, it even has redundant power and cooling, and is a bargain at $6600 for a 1TB storage config" WTF!?!?!

C'mon guys, this has been the hardest thing to swallow since deciding to switch from PC to Mac that is having to listen to the Mac "cult" followers tell me to never question what "God" AKA Steve Jobs/Apple has given us, simply we should give thanks unto them and be happy with what we have, after all "God" doesn't make mistakes.
Granted the Mac Pro kicks @$$ and at $2299 (edu. dis.) I can't even buy the parts from Newegg at that price, not to mention I wouldn't get the awesome/quiet case or the impressive OSX which I am really starting to like but PLEASE, Apple is not God and they do make mistakes and bad calls sometimes!!!

Here is the bottom line on the RAID thing. The Mac Pro's motherboard is an Intel 5000x based "Greencreek" or "Blackford" Northbridge with the ESB2 Southbridge. Why is this important you ask?, because the ESB2 Southbridge from Intel supports HARDWARE based RAID 0/1/5/10 across the 6 SATA ports. Not to mention that every 5000x based dual Xeon motherboard with the ESB2 Southbridge that I have found for sale does indeed support hardware RAID 0/1/5/10.
So if I were to buy this same MB for a PC Workstation or Server, I would simply boot the system, go into the EFI or “BIOS inside EFI Shell”, yes all these boards have EFI support as mandated by Intel although most use it to run a BIOS unlike apple. Next I would enable RAID as my desired option for the SATA controller which ENABLES the Intel I/O RAID Subsystem controller which is located INSIDE the actual Southbridge chip. After rebooting, the RAID firmware in the Southbridge will presents a screen (only if more than 2 hard drives are connected) that allows you to setup your desired hardware RAID 0/1/5/or 10 before any OS is ever booted.

So to use the hardware RAID built into the Southbridge chip on the Mac Pro we need two things from Apple:
1. A way in EFI to Enable/Disable SATA RAID on the Southbridge, heck it could even be a cool new “hotkey” sequence 
2: OSX RAID drivers, and since we already have the regular SATA drivers, it should be very easy to write RAID drivers for OSX. I bet there are already BSD/UNIX/Linux RAID drivers out for this Southbridge making it that much easier to port to OSX.

This hardware solution is better than any software option currently on the Mac, not to mention RAID 5 support across 3 or 4 drives. This would be more secure, robust, reliable, easier to setup (try setting up RAID 10 on the Mac Pro , it not fun. Also XP via bootcamp could reside on a FAT32/NTFS partition on the RAID setup instead of a separate hard drive outside of the RAID like I am going to be forced to do.
A slipstreamed disk with the RAID drivers installed would need to be made but as those who have installed XP already have found out, you have to do this anyway if you want any decent performance in XP on the SATA drives.
There is really no argument for Apple not doing this, unless you consider that Apple would rather have you spend a minimum of $6600 to get RAID 5 support as was suggested in a post above.

I guess I just don’t like feeling “limited” as I sometimes do on the Mac, bootcamp has given me the opportunity to switch b/c I can still play an occasional game when it comes out rather than waiting a year for it to be ported to Mac and I can still use certain Windows only apps that I like. I am finding myself using XP less and less though. The new Mac Pro is my second Mac purchase (I purchased a MBP last April) but I do hate being told by other Mac users/loyalists that I should be happy/satisfied with an obvious limitation that could easily be fixed. One such example was yesterday when I found out that the Mac Pro lacked Photobooth and FrontRow, when expressing my dismay I was responded to with comments like this, “the Mac Pro is a Workstation, not a “Playstation” so that is why Photobooth and FrontRow CAN’T be installed, if you want a toy, buy an iMac or Mac Mini”. It is this general sentiment that makes me shake my head and think to myself, do I really want to “Think Different”? If that guy new what he was talking about he could have informed me that Photobooth can actually be installed (as I later found through searching) but that you have to actually connect the iSight or other Firewire based camera to the Mac Pro first before installing, Frontrow however is a no go right now.
Anyway, a long winded post I know, bottom line is that I am really excited to get my new Mac Pro and am obviously willing to live without hardware RAID if that ends up being the case. Allowing hardware based RAID 5 through the supported Southbridge though would really make this system great, not to mention a lot of new customers really happy.

 

[Macinposh]

Yo,Altimeter.

I share your sentiments..



A quickie for you, have you charted what kind of speed differencies you could expect between raid 0+1 and 10 with macpro,dealing with both big and small files.

Getting a same kind of setup (4x500GB+160GB) and I am thinking of putting them in a 0+1 config.Or a 10.
Just that I havent found any comparison in the speed between those two systems,so I´m in a bit of limbo at the moment.

 

[cube]

Why not add an extra drive and use raid 3 or 5 with a hardware controller. Then you get improved performance and it doesn't matter if a drive fails.

How are you going to connect the internal drives to this controller? This is a design flaw of the Mac Pro.

 

[tyr2]

Getting a same kind of setup (4x500GB+160GB) and I am thinking of putting them in a 0+1 config.Or a 10.
Just that I havent found any comparison in the speed between those two systems,so I´m in a bit of limbo at the moment.

Generally it's considered better to go for RAID10 rather than 01 as 10 offers better hardware redundancy.

i.e. If you have disks ABCD.

With RAID 01, if A fails (in the stripe with B) you cannot lose C or D but B can fail.
With RAID 10, if A fails (in the mirror with B) you cannot lose B, but C and D can fail.

As such it gives you slightly more redundancy. Also the time taken to resync the failed disk is significantly reduced with RAID10.

At least this is how I assume it works on OS X, it is on practically any other RAID management stuff.

However having said all that I'd be interested to see some stats on performance comparing the 2 layouts.

 

[Macinposh]

As such it gives you slightly more redundancy. Also the time taken to resync the failed disk is significantly reduced with RAID10.

At least this is how I assume it works on OS X, it is on practically any other RAID management stuff.

However having said all that I'd be interested to see some stats on performance comparing the 2 layouts.

Yup,that´s what i was thinking too.

The redundancy thing is a bit non issue, like 0.33% compared to 0.67% (in 10) is blah,in that sense that i have a spare 500 to throw in in a case of a incident.
Resync time is of a bit of a issue,but not that much. In case of a incident,i have a another computer to throw in for that down time.So..

But the performance is something i am intrested in. Albeit all the reports seems to show/tell that the difference between 0+1 and 10 is non existant in usuall setups.
But.
I dont know about MP, if that is classifed as usuall setup.
Yet.




So when you guys get your stuff, what benchmarks are you planning to run? Xbench is a phoo, so what else is there good for general bm, or especially to test HDD performance/Raid?