View Full Version : Mission Critical RAID Needed

12-08-2001, 04:24 PM
We're running a "Mission Critical" 4D database on a G4/733 tower. We have a programmer that has customized this database for us. It is currently running on a hardware RAID (I don't know the manufacturer) which is currently 5 years old and hasn't missed a beat. It is time to replace the hardware RAID for speed and end-of-life concerns.

I need some advice on:

- Hardware RAID vs. Software RAID? Is Hardware RAID more dependable?
- SCSI U2W (LVD) vs. U160?
- Seagate vs. Maxtor vs. anyone else?
- Recommended PCI card?
- RAID 0 vs. RAID 1-5?
- Websites I should visit for research?
- Any other thoughts you may suggest?


- This server and 4D database CANNOT GO DOWN! This is my job we're talking about.
- It needs to be as fast as possible
- Money is NOT a major issue
- Any current RAID will probably be faster than our 5 year old RAID
- Stability and redundancy outweigh speed
- I have another G4/450 that I could use as a test before running on the true server.
- 4D currently backs up the database at midnight. It could mirror itself, but it would take an unacceptable hour to do this.

Your thoughts are extremely appreciated.

[This message has been edited by MacCowboy (edited 09 December 2001).]

[This message has been edited by MacCowboy (edited 10 December 2001).]

12-09-2001, 03:17 AM
I can get this started but cannot address all of your questions.

- Hardware RAID vs. Software RAID? Is Hardware RAID more dependable?

I have no experience with hardware RAID other than chipping in to help with a few who have come to the Gurus forums with hardware RAID problems. I can say that software RAID can be very dependable with the right equipment. That means a Burly RAID box, ATTO UL3D, SoftRAID, Granite internal (Burly) and external LVD cabling and LVD terminators, and the latest Seagate Cheetahs U160 and U320. How many Cheetahs and how bid depends on your needs.


SCSI, either U160 or U320 LVD.

- SCSI U2W (LVD) vs. U160?

The U2W LVD drives are no longer current tho you may find someone that has them. The U160 and U320 LVD drive are the current state of the art and in many ways far superior.

- Seagate vs. Maxtor vs. anyone else?

Seagate LVD drives

- Recommended PCI card?


- RAID 0 vs. RAID 1-5?

This one I will have to defer to someone else. I have only built RAID 0 for a legacy machine (PowerTower Pro) and a G4-800DP.

- Websites I should visit for research?

Start here http://www.macgurus.com/ and you will find huge amounts of info along the way. Others can help with more. I purchase all my stuff from the Gurus. Despite my title, this is volunteer work. I am not an employee. I live on the left coast and Hardware Haven is on the right coast.

- Any other thoughts you may suggest?

Here is a shopping list. I will assume a six drive setup:

Burly MAP5083 8-Bay 5.25-in SCSI Encl w/ 15-ID Switches $334.99 ea here http://www.macgurus.com/shoppingcart/obj_show_page.cgi?mgscsienclosures.html

Granite TPO LVD internal cabling inside the Burly, two (2) of GD2682 Quad 68-pin Int TPO LVD Ribbon Encl. Cable $148.99 ea on the same page as the Burly and near the bottom. You will be building a dual channel striped RAID.

Granite external LVD cabling connecting the ATTO UL3D to the Burly, two (2) of GD4911 Ext. 68-pin .8mm to 68-pin MicroD 3-ft. Cable $159.99 ea here http://www.macgurus.com/shoppingcart/obj_show_page.cgi?mgscsicables.8mm.html for the dual channel.

Granite LVD terminators, two (2) of GD6299 68-pin MicroD LVD Active Diagnostic Termination $99.00 ea and for diagnostics, two of GD1636 Remote LED Indicator (for use with Terminators) $19.00 ea both here http://www.macgurus.com/shoppingcart/obj_show_page.cgi?mgscsiterminators.html

ATTO ExpressPCI Dual-Channel Ultra3 SCSI Host Bus Adapter $457.99 ea here http://www.macgurus.com/shoppingcart/showrampage.cgi?attoboards.html

Eight (8) of Ultimate 5.25-in Hard Drive Cooler w Dual-Fan, Heat-Sink $34.99 ea because, even with six drives, we recommend filling an 8-bay Burly. Here http://www.macgurus.com/shoppingcart/obj_show_page.cgi?coolingdevices2.html

SoftRAID HD Formatting, RAID 0, 1 Utility $144.99 ea here http://www.macgurus.com/beta/obj_show_page.cgi?mgscsiraid.html but note that SoftRAID currently does not support OSX. http://www.softraid.com/ and lots more reading there.

Cheetahs here http://www.macgurus.com/shoppingcart/showrampage.cgi?mg_hdseagates.html

Seagate Cheetah 9.1GB Ultra160 4MB cache $194.99 ea
Seagate Cheetah 18.35GB Ultra160 4MB cache $239.99 ea
Seagate Cheetah 18.35GB 15k Ultra320 8MB $359.99 ea
Seagate Cheetah 36.7GB Ultra160 4MB cache $444.99 ea
Seagate Cheetah 36.7GB 15k Ultra160 8MB $589.99 ea
Seagate Cheetah 73.4GB Ultra160 4MB (1-in) $799.99 ea

My guess would be the Seagate Cheetah 18.35GB 15k Ultra320 8MB $359.99 ea or
Seagate Cheetah 36.7GB 15k Ultra160 8MB $589.99 ea, six of them? These are both what we call the G2 (Generation 2) X15's.

Six of either of these drives striped will give about 200MB/s sustained read and write and to nearly the inner tracks of the drives.

If you prefer to have this Burly built up and tested, magician is the man who does this work and can give you a quote.

If I have forgotten anything, it's late. I'll look at this post in the morning. k

[This message has been edited by kaye (edited 09 December 2001).]

12-09-2001, 10:00 AM
I got an email that ATTO has fibre channel for Mac OS X and then there was a note on MacNN last week regarding a hardware RAID solution starting at $4995 I think. Check on when ATTO will have UL4D available for U320.

I'm disappointed in the 10k Cheetah but pleased with the latest X15.

While most people here are opposed to SCA drives in non-SCA environments, I think the Mac as a server is still a work in progress and a true server or network storage solution, maybe OS X Server.

OS X seems to turbo charge SCSI I/O but it is still sounds incomplete. ATTO has drivers for OS X and SoftRAID is hoping to have theirs early 2002.

I would be talking to the vendor of your current hardware RAID and see what they have today and 4D of course. I'm surprised you stayed with your setup this long.


12-09-2001, 10:04 AM
Thank you for your suggestions. I'll review in detail and probably follow-up this post.

12-09-2001, 12:06 PM
I thought the only benifit of Fibre channel over Ultra160/320 was cabling distances. Fibre channel can go upto 1 mile IIRC - right?

10K Cheetahs (and other 10K drives) are really old news. I doubt Magician has used a 10K drive in years. I just might have it in my budget to get a 15K Cheetah - one of these days.

If there are supported SCA SCSI cards (for MacOS 9, 10, etc..) then I would think an SCA drive should work fine. I'm fairly sure that there are not any for 9 (classic) but because of system 10's unix roots it is possible that there is an SCA solution. I would hope it is rigoursly tested. After 10.1 came out SoftRAID said they they are hard at work writing RAID drivers for X and that they need to go through some serious testing. It seems while system 10 is very stable, much of the features a Mac user would take for granted are either -
not there (where is the chooser!?)
not stable enough (some dual monitor setups are unstable)
not versatile enough (limited built-in RAID in 10.1)

I would think a mirrored (RAID-1) would be the way to go. I guess I am like a poor version of Kaye - since I also only stripe my drives for legacy system but my drives are older and slower... I would think that a mirrored RAID would give you the same write speed as any single drive, but you read speed should actually be a little faster - since it can read off both drives for a 'striping effect'.

I am not sure if SoftRAID can mirror more than two drives into a single volume. So if you need a REALLY LARGE mirrored volume you may need to get the 72GB (10K Cheetah) or 180GB (7.2K Barracuda) and mirror them.

Mirroring should give you the best data integrity for the drives. RAID-5 is more efficienct since you only loose 1/3 of your drive space (to parity check?) but I would think a mirror (RAID-1) would be more robust. You should of course also have tape backups and off site storage for critical data. The VXA look like a good option. They are way cheapter than DLT 4 tapes and VXA is probably more reliable anyway. Retrospect/Dantz is also working on a version of their software for X - they have a beta out right now. If you get the current version for classic - they say you can get the new X - Native version for free.

I would back everyone else up that SCSI and Seagate are the way to go. You can setup RAIDs for IDE/ATA, but then IDE is only rated for 3 years, not 5 and from what I understand they are not good for setting up mirrored arrays. You might want to check out http://www.xlr8yourmac.com

They have a huge drive database. Mike Breeden (the site owner & operator) also has fairly in depth articles on drive arrays - both SCSI & IDE/ATA.


To boldly go where no english professor has gone before! -)

12-09-2001, 09:42 PM
On SCA and such....

dragon_x...you talked about SCA cards...there is no such thing. The whole thing with SCA is that it is a means to mate a drive with a backplane with a Single Connector Attachment. Also, SCA is really not that hard, if you have the hardware.

My 9600 runs SCA drives ONLY, in a 12 drive SCA rack. The key to using SCA drives effectively with a Mac system is having an enclosure designed for SCA. These range from 3-4 drive containers: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1307797108
Through 10 drive cages: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1307473289
All the way through 30, 60, 120, etc. drive SAN boxes.

For those of you who have SCA drives, and are sick of the adapter headaches, I can verify that I have a used a 3 drive LVD cage in a PTP (where it mounts nicely), with every OS for 8.5 - 10. It is not sofware dependent. As long as your OS supports your SCSI card, the drive cage is 'transparent'. The cage has a 68 pin connector, some ID selectors, a Molex, as well as a 68 pin out (usually where the terminator goes).

Here's the upside to a cage like this:
If you buy a cage for $65-80, and 3 SCA drives, which are usually 60% the price of 68 pin drives, a non terminating LVD rated cable, and a GD 68 pin LVD terminator, you're still prolly saving about $100.

The downside:
The cages look hideous.
Dual channel requires dual cages (my external 12 drive rack is dual channel).
If you buy a cage without sleds (drive carriers) you will get ripped off buying sleds.

So if you have some SCA drive you got 'unexpectedly', instead of going through the headaches of buying adapters, look into a cage, and use the drives like they are supposed to be used.

[This message has been edited by chrismenke (edited 09 December 2001).]

12-10-2001, 02:01 AM
My brother has described virtually identical setup at Apple for their server data storage. Of course, they're runnin' a terabyte per box on RAID 5. Lots and lots of rack mounted drives. I heard also of them having HUGE ram based buffers that allows some serious throughput. They can dump data on the buffer in gigantic gobs that then gets written unseen by the server.

12-10-2001, 10:07 PM
Well why didnt you say so. Still SCA is a PAIN!
Besides I usually say ADAPTORS ARE EVIL! http://macgurus.com/infopop/emoticons/icon_smile.gif

12-12-2001, 12:37 PM
Interesting how this discussion has gotten off-topic so quickly.

The current hardware RAID5 box we are running is from APS Tech. Again, this box has been spinning for almost 5 years without a glitch. I'm currently settling on hardware RAID vs. software RAID. The dependability of a dedicated box to handle the "recovery" in the event of a failure outweighs the throughput we'd achieve with RAID0 or RAID1 and a software RAID solution.

If this 4D server was not so Mission-Critical, and throughput was top-priority, I would probably be concluding differently.

It is also my understanding that MacGurus does not recommend hardware RAID solutions. Whether this is due to firmware incompatibilities or other factors I am unsure of.

12-12-2001, 07:15 PM
I've seen the APS catalog. I do not remember any RAID-5 setups... but then that is the TOP END and probably beyond the price range of their regular catalog.

I am sure the APS RAID-5 box is a 100% reliable over its MTBF rating... maybe longer?

Of course reliability is the MAIN goal - this is often overlooked in the Ghz Windows world. A RAID-5 gives you good data integrity (similar to RAID-1/MIRROR) and good speed (similar to RAID-0/STRIPE). To my knowledge there is no RAID-5 available in software. SoftRAID LLC would have released a RAID-5 driver IF it could pass their rigourous quality tests. I do like SoftRAID in that it is simple, fast, flexible and reliable - you can not ask for much more from a software disk array.

I have not put together or run any hardware based RAID solutions on any mac. I am sure it can be done, but the price is out of my budget and I really do not have the need for something like at - at home anyway. I would think that the Gurus do not recommend hardware RAID on the Mac because they have not found a good solution. I'm sure a solution is out there - maybe you have found it?

If the hardware RAID - 0, 1 or 5 were setup in a way that the drive(s) and/or volume(s) would appear as a single normal drive (HFS, HFS+, UFS) then I would think it would work fine. There would be no firmware issues because the Mac would not even need to be aware of any 'firmware'.

I would be interested if you have any knowledge of a RAID-5 option available and certified for Mac OS (classic or 10)... just give us the link!


So Apple is running PMacs with a hardware based Terabyte RAID-5 setup?

I would assume that the systems are running on Mac OS 10/ 10 Server.

To boldly go where no english professor has gone before! -)

12-12-2001, 10:05 PM
Would this not work?..

They can be set up as Raid 0, 0 + 1, 3 and 5....


12-12-2001, 10:06 PM
And for those who like to tinker...

12-13-2001, 12:25 AM
Some more food for thought:
www.archion.com/main.html (http://www.archion.com/main.html)
www.studio-stuff.com/adtxraidjinfo.html (http://www.studio-stuff.com/adtxraidjinfo.html)
www.raid5.com/ (http://www.raid5.com/)

You will definitely want a dual channel setup for max speed, Seagate X15 Ultra160 drives for speed/reliability and probably two separate ATTO UL3S PCI host cards to achieve every last MB/s. I cannot personally vouch for the firmware compatibility of any of these RAID boxes but, since they are OS-independent systems which show to the host adapter as a single SCSI device (per channel), I can't imagine where the incompatibility would lie. Looks like you have a separate dedicated terminal connection to control the parameters of the setup in most of these boxes. I would put direct questions about use with MacOSes to each manufacturer.

[This message has been edited by MacMikester (edited 12 December 2001).]

12-14-2001, 12:52 PM
Interesting short take http://www.amdmb.com/article-display.php?ArticleID=54&PageID=10 on Hardware v. Software RAID. k