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colejd
05-16-2007, 02:50 PM
I am a raid nubie but have lotts of Mac experience (1986 Mac Plus, etc.). I have a G5 dual 2 PCI-X with 2.5 Gigs that I want to run a 1 or 1.5 T raid box out of. I know a bit about hardware raids via cards (usually raid 0, 1, or 5 at the most), however I am unfamilliar with what you would do if you wanted to use Apple's DU to set up a software raid. Is there less expensive eSata PCI-X card that has at least 2 external ports? Can the hardware raid cards be told to let DU do the configuration?

ricks
05-16-2007, 04:34 PM
Not many hardware RAID cards to choose from, but yes, most all of those that can mount the drives JBOD can then use DIsk Utility to create a RAID.

Any plain old host card like these (http://www.macgurus.com/productpages/sata/PCISATAHostCards.php) can be used with DIsk Utility or SoftRAID (www.softraid.com). This method is very low overhead on the CPU, very simple and fast. And at least 99% of all Mac RAIDs are created this way.

most of our storage sales today uses software based RAID with SATA port multiplier systems (http://www.macgurus.com/productpages/sata/PortMultiplicationGuide.php). Port Multiplication has pretty much taken over the storage market for 4 or more external drives. It is simple, expandable and fast.

Rick

colejd
05-17-2007, 06:32 AM
Do you know what levels of raid DU is capable of? Is softraid a more capable tool in this area?

ricks
05-17-2007, 08:56 AM
On a Mac software RAID is almost always Striped, Mirrored or Spanned.

I have yet to ever test a RAID5 software solution that didn't eat the CPU. Last one I tried used in the neighborhood of 95% of the CPU during writes. Even more when you had a degraded array that was running off of one drive short.

In my opinion you gotta have a hardware RAID to do RAID3 or RAID5. Definition of hardware RAID is that the card or controller must have its own processing.

Rick

colejd
05-17-2007, 01:37 PM
Is there a card that supports hardware raid 5 on a G5 mac (PCI-X)? Most of the ones I see support it under Windows but not OSX.

ricks
05-17-2007, 02:46 PM
Hardware RAID implies that the card has a processing CPU on it to handle the overhead. There might be a HIghpoint PCI-X card that really is hardware RAID, most all their older stuff was software RAID where the software is stored on the cards firmware. Even though they call those cards hardware RAID they are not. (true of most PC RAID cards as well, if they cost less than a few hundred they are probably not hardware RAID) My problem with Highpoint is the the company's support is terrible and they always have buggy products. So we don't mess with them at all. They may have a product that fits your description though.

Other than that, you can go with a Huge Media Vault or a Medea or similar unit that has a SCSI host bus and the RAID controller inside the enclosure. There are also a TON of Firewire units that have a RAID unit in them. they aren't fast nor are they very complex in management, but for the most part they work pretty well.

Rick

unclemac
05-17-2007, 11:42 PM
What Ricks said.

The highpoint stuff looks like it is getting better, but nobody here (that I am aware of) is using any of their newer products, so I don't think you will get a recommendation. Most of the regulars here are conservative - perhaps to a fault - about using what works, works well, and is supported and continue to work and be supported for the forseeable future.

As Ricks said, there are many external solutions, but most of them are geared towards general purpose storage, not fast scratch space......so it really depends on what you need and expect. If you would be happy to have your 1+TB that gives you about the same performance as a single interal PATA drive (30 - 60 MB per second transfer speeds) then you have plenty of RAID boxes to choose from.

If you need more speed than that, you will have to spend more $$$, regardless of the solution. MacGurus is selling one of the few fast RAID 5 hardware cards for Macs: 3ware. It is a complete system with external storage though, not aware of any way to buy just the card.

unclemac
05-18-2007, 12:01 AM
This is getting kicked around from time to time.... a couple other threads to pursue:

http://www.macgurus.com/forums/showthread.php?t=23551&highlight=RAID
http://www.macgurus.com/forums/showthread.php?t=23409&highlight=RAID
http://www.macgurus.com/forums/showthread.php?t=22721&highlight=RAID
http://www.macgurus.com/forums/showthread.php?t=22894&highlight=RAID

Nicolas
05-18-2007, 12:44 AM
Yep, as the Rick and Uncle are saying.

If you want a fast RAID5-subsystem with high thruput you'll need to go
to Fibre or SCSI because your mac is PCI-X and lags on PCIe the 3ware is no option.

Stuff like the SCSI>SATA RAID from Huge is the only way to go.
Yeah there are others (EasyRAID, Medea, Infortrend) as well at even higher cost.

Regards

Nicolas

colejd
05-18-2007, 07:03 AM
I appreciate the advice. To be more specific, I am trying to set up an external raid for digital asset management (DAM) for a large number of raw digital camera files. I mostly want safety (i.e., redundency of files), and expandability, and finally speed (in that order). Any thoughts?

ricks
05-18-2007, 11:19 AM
I like a simple setup. Simpler the better as simplicity usually = reliability and speed. All the data at MacGurus is stored on Burly enclosures and backed up to identical Burly enclosure. These are each in RAID0. The cost basis is great and the robustness of Disk Utility or SoftRAID RAID0 combined with the Burly PM enclosure is superb.

Drive failures are the least likely cause of data loss, so we don't use a RAID5 that protects only from a drive failure. We prefer to run a software utility like ChronoSync or SyncronizeProX to run the backup. This protects from almost everything including a drive failure.

Been doing it that way for years. I spend some time now and then on the phone with Peter Krogh, he is one savvy dude. I have learned a lot from him in just a few minutes of conversation here and there. You couldn't be following a better path. One thing I would say is that Peter tends to complicate things more than I would with servers and fancy storage scenarios based on a server. I like my photo data attached directly to my fastest workstation. I want to monitor my backup every morning as soon as I sit down. I use SyncronizeProX for my backup utility and it runs every night. As soon as I sit down I check it since it will be the application in front on my monitor.

My backup is not attached to the workstation since we all share a backup location here. SyncPro mounts the backup volume automatically and makes its backup over the LAN. I would feel just as comfortable with the backup Burly attached to my workstation. Simpler - For us having an old G4 tasked to backups from all the workstations is simpler than every computer having backup attached. Cheaper as well.

RAID0 with port multiplier enclosures is very expandable. Up to 20 drives attached to a single 4 port host card. It is really expensive to expand a good RAID5. It is really cheap to expand a port multiplier system. You can either reconfigure with more drives in the RAID0 or better yet, just build a second big volume and keep it separate. Either works though depending on individual needs.

Software RAID0 is so simple and low overhead that it works for a huge majority of our customers. Most all of them are running pairs of individual drives or RAID0 arrays backed up to each other. Until we see better offerings in the hardware RAID market there really isn't much there that is expandable and cost effective enough when you add in the cost of a backup.

Rick