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View Full Version : Which external scsi raid solution?



Seti Orion
03-01-2006, 12:53 PM
I have 2 smaller raid arrays in my system and Im running
out of space quick!

I need an external raid solution.

Are 15K rpm scsi 160 drives the only way to go? $$$$

I need to be able to record at least 2 uncompressed (3 would be nice) streams while playing back a few ddrs
and running some other things to just to know that I can.
While doing all kinds of fades and transition fx etc...

I'm looking to start of with a terabit but expand to several in the future.

any ideas?

John Perkins
03-01-2006, 03:04 PM
That is a tall order, reading and writing that many streams simultaneously really puts a load on the RAID.

You might want to use two smaller raids, one for reads and one for writes.

Use U320 if at all possible, all new drives are U320. For the kind of use you are asking for, I would go with 15K, but if you split the workload into two drive sets, 10K drives should work fine.

There is no way to get that kind of performance for any usable length of time from SATA, so yes, SCSI is the way to go. The access times just aren't very good and when you are reading and writing that many streams at once, a low access time is the key factor.

Seti Orion
03-01-2006, 03:06 PM
Thanks for reply

You know of any good external scsi raid boxes?

John Perkins
03-01-2006, 04:36 PM
I've liked the Rorke Data MaxArray boxes. I had an 8 drive 15K box that would do just about anything I asked of it.

Even their Galaxy HDX (many SATAII drives connected to SCSI, RAID5) seem to work very well, but I don't remember them being able to keep up with what you need.

Seti Orion
03-01-2006, 04:46 PM
do you know of a box that would do what I need?

SCS5
03-02-2006, 07:41 AM
Look at Medea external Drives ( Medea.com??) . We've used these for years. They have the best price, performance ratio.

Videonut
03-02-2006, 04:42 PM
There is no way to get that kind of performance for any usable length of time from SATA, so yes, SCSI is the way to go. The access times just aren't very good and when you are reading and writing that many streams at once, a low access time is the key factor.

John, why can't the SATA drives give that type of performance for any length of time? I was under the impression that the SATA drive technology is built around the SCSI technology. Would the SATA give good results for less strenuous criteria, such as 2 layers of DV-Type 2 and a layer of RTV. Also any thoughts on the capabilities of Firewire 800 drives.

John Perkins
03-02-2006, 05:18 PM
NewTek only recommends SCSI drives. They work. From the specs page: Four 10,000 RPM Ultra 160 or 320 SCSI hard drives or three 15,000 RPM Ultra 160 or 320 hard drives

We've also tried SATA. We don't own stock in SCSI (if there was such a thing) and we don't make any more money if you buy SCSI. We just know that your job depends on it working and we have had problems with SATA and IDE in our testing. We put some harsh loads on drives because we do everything in full quality, many layers at a time.

It seems to be a problem with the access times, IMHO. The drives can't skip from one file to another fast enough. Sometimes everything plays back great, others it will skip. You just never know. Maybe with the 10,000RPM SATA drives, but those cost close to SCSI anyway. I'd rather get the real thing for a little bit more money.

That said, you have to build a system that fits your budget and needs. If you only need a couple of layers of DV and are willing to deal with skipping sometimes and less realtime capability, stripe a couple of SATA drives and go with it. It will probably work, but we can't tell you that and know that your project will play out correctly every time.

tmon
03-02-2006, 08:03 PM
Last time I checked, which was quite a while ago, Medea (now AVID!) didn't offer a good hot-swap solution. I don't know about Rourke. Either way, I'd have that on my spec requirements, but that's just me.

I'd definitely go with U320SCSI in your situation. As I understand it, SATA performance degrades much more quickly than SCSI when the drives start getting full.....

John Perkins
03-02-2006, 11:30 PM
I need to qualify that these are my personal experiences from before I worked at NewTek, not NewTeks views...

I haven't seen anything with redundancy that can handle everything he asked for.

The closest I've come are the Galaxy HDX which is hot swap and RAID5. They have a really good RAID controller that can actually keep up somehow. I was using a unit with (I think) 8 drives and it worked great for editing and single stream recording. I'm not sure how it held up on multiple streams on record because I didn't need it.

The MaxArrays are about as fast as you can get, but with RAID0 you can't do hot swap period.

I tried one REALLY BIG (hint, hint) enclosure that couldn't keep up with one stream of recording while playing one, even though it was rated for HD. We fought with that for two weeks with their engineers before the company gave up and we shipped it back. Their RAID controller wasn't really designed for simultaneous read/write.

I like the easily removable bays, but unless you need 100% uptime, like a playout system for a television station, I can handle shutting down to change a failed drive.