PDA

View Full Version : 6 drive IDE RAID 0, 1, 3 & 5?



PENDRAGON18
12-26-2000, 01:59 PM
While searching for something else I found this-
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>ARENA - World's most advanced RAID system for Macintosh
Finally, the cost effective, easy to use high performance RAID solution is here.

Arena is one of the most sophisticated SCSI RAID Arrays. It comes in All-In-One enclosure that has built in RAID level 0, 1, 3, and 5 with SCSI III interface, and 6 hard drive hot swappable trays. All you have to do is to mount IDE hard drives into the removable trays and plug them into the enclosure. You get the flexibility of choosing the size of the hard drive that matches your requirements.<HR></BLOCKQUOTE>

Here is the link
FREAQY-RAID (http://www.macally.com/new/newarena.html)

Not that I am in the market for this, but is it ANY good?

I am fairly skeptical. Not sure how they fake the Mac out into thinking it has 6 SCSI drives... I guess they could use 3 ATA/IDE channels.

ChrisYip
12-26-2000, 02:53 PM
I have a colleague who has several of these Arena systems in his lab - he uses them for his database analysis work. Swears by them - then again, he has a 218-processor cluster and an unreal need for disk space (i.e. a pending analysis run will take potentially up to 300 GB of disk space ...) - he already has > 1 TB of disk space on his cluster...

I was looking into them as well (a bit pricey) - they have an on-board processor which I suppose takes care of accessing the hardware RAID and allows it to appear as a single SCSI device to the computer.

They look very slick - hot swap power supplies and drives - you can buy them as a bare chassis and populate them yourself or have Arena do it for you. I think this system is being OEM'ed to a number of other folks. Fantom has something that looks very similar.

Chris.

magician
12-26-2000, 03:21 PM
you are correct, Chris. This unit is indeed being OEM'd to a number of vendors. We are testing one now in the basement, a SCSI LVD version, with eight bays. It delivers 50MB/sec sustained thruput, both reads and writes, regardless of how many drives are installed. The problem we are encountering with the unit at this time is, it refuses to actually use more than three drives at a time, regardless of whether we select RAID 0 or RAID 5. Under RAID 1, it will only use two drives.

we're shrugging our collective shoulders, and waiting until the dust settles from the holidays before we talk to their tech support. We suspect a firmware update will be required. We've shuffled caddies, shuffled drives, and can't make any sense of it. It's disappointing, as they are pretty units. Not the most durable, and a little expensive, but ok. If we can actually make them work without further hassle, we'll consider them more seriously.

at this point, however, we stand by previous posts. All hardware RAID we have tested on the Mac exhibit firmware problems which prevent us from rendering an endorsement.

Allen Wessels
12-27-2000, 01:34 PM
Their web site doesn't really give a whole lot of information.

I don't know how you could make an IDE RAID without one dedicated IDE channel per drive. IDE AFAIK can't write to two drives on the same IDE channel at once. You could have separate RAID volumes use alternate drives on the same channel.

magician
12-28-2000, 04:14 AM
the secret is in a hardware backplane.

IDE hardware arrays don't work as well as SCSI, but they are more affordable. We have yet to find one that works to our satisfaction on the Mac.

Jay the Unnicknamed
01-01-2001, 08:02 PM
Alan ... to more directly answer your question ... all these devices have their own CPUs inside them to manage the IDE drives, and as many separate IDE channels as drive bays. So you can think of the array as being a whole computer unto itself, with six IDE buses, each with its own drive ... and the whole "computer" is dedicated to the task of just acting like one gigantic hard drive.

By the way, the ARENA is not the most advanced device of this type that I've seen ... others have eight or more bays, and support RAID 0+1, which is a neat trick. (You stripe as many drives as you want, up to four, then mirror all of them on the same number of drives. So you get four-drive RAID 0 performance i.e., faster than RAID 5 with complete redundancy.)