March 5th, 2004, 09:00 PM
SATA RAID 5 or SCSI RAID 0
At first, I was planning to replace my IDE RAID 0 array with a SCSI RAID 0 array. Then last night I got to thinking about perhaps using the Promise FastTrak S150 SX4 with its RAID 5 capability. The price would be about the same for both setups with similar sized disks. I was going to use Maxtor Atlas IV drives for the SCSI route and Western Digital Raptor drives for the SATA route. Then I saw a performance test that someone had done with four 36GB WD raptors in a RAID 5. The write speeds were between 6 and 8 MB/sec, which is terrible for what I would need. Does RAID 5 really have that low of a performance when it comes to writing to the array? I did read that this Promise card isn't 100% truly hardware RAID, so I wonder if that's why it scores so low. Has anyone else tried this RAID card?
If you saw my other post about RAID 0 performance, I'm using this array to capture uncompressed video at 640x480, and I need a minimum of 20MB/sec sustained write speed. I was hoping to upgrade to some reliable SCSI drives when I thought about doing RAID 5 with this SATA card. If anyone else has any good ideas about a high speed HDD writing setup, I'd be interested to hear what you have to say. Thanks.
March 5th, 2004, 09:02 PM
With 4 drives, why not run SATA RAID0+1? As I understand it, RAID5 doesn't really make sense unless you're using arrays of 5+ drives. Too much seeking to write all the recovery data.
Of course, a single 160gb 7200rpm would probably natively beat a 2x36gb RAID0 from sheer platter density. Or that new 300gb 10k rpm Hitachi? It has a write speed of 89MB/s
Last edited by grover; March 5th, 2004 at 09:13 PM.
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March 5th, 2004, 11:13 PM
I am using a Highpoint Rocket Raid 100 card with 2 X 80 gig Seagate IV drives to capture uncompressed avi from an Svhs tape deck.
Virtual Dub says I have a sustained Write speed of 25061KB/s.
Sandra shows a Sequential Write speed of 40MB/s but a Random Write speed of 11MB/s. I do not have any trouble capturing 60 minutes of tape on 70 or 80 gig of space.
I know Raid 0 is not the most reliable setup but I delete the large capture after converting to the desired format.
March 6th, 2004, 02:51 AM
Wow, nice to see I'm not the only nut crazy enough to be capturing uncompressed video with VirtualDub.
Oh, and I checked on that 89 MB/sec speed on the Hitachi. Look closer:
89 MB/s maximum sustained data transfer rate
Doesn't say write speed, most likely that's a read speed. I've seen stats like that before, and they usually are read speeds.
The funny thing is, I've been using my Maxtor 80GB drives in RAID 0 for about a year now, with little or no trouble. Only recently I guess have the drives been developing bad spots that the drives have internally relocated to the spare sectors. I wouldn't be surprised, as I do tend to give them a lot of usage. I often capture between 3 and 5 hours of video per week, plus there's all the editing I do too. This was why I was looking to get some better drives more suited to such heavy usage, like 10,000 rpm SCSI drives. Who knows, I may do this for money someday...
March 6th, 2004, 11:20 AM
I have been infected with the Video Editing bug. Having some precious content on vhs tapes was the precusor to becoming infected.
I have a Sandra graph that shows the Drive Index numbers of different drives compared to the tested drive.
My ATA 100 Raid setup shows a Drive Index of 44734kB/s and the Sequential Write rate of 41MB/s.
With the Maxtor SATA150 outdoing the SCSI 320 by 6.4MB/s and the Drive Index at 99800kB/s, that puts it at 97 MB/s, yes?
My hardware is on the low cheap end of things. I wanted to get a 3 Ware card that supported Raid 5 but the PCI bus in my Soyo KT333 is not compliant for any of the newer Raid cards including SATA.
Checking my block size, I discovered that the last time I set up the Raid Array, I set it at 512b. I broke the Array and reset it at 64K, formatted and was back up in less than an hour. If there is no useable data on your array, formatting may clear up your setup.
My choice for speed would be 4 Raptor 74 gig in a Raid 0+1. Now, let me try to attach the Graph.
March 7th, 2004, 02:03 AM
That's an interesting graph. I think I know why the Maxtor SATA drives beat out the SCSI ones though. It looks like the top graph was for a 4 drive RAID 0 array, and the SCSI was only 2 drives. Also, what is that drive below the SCSI? MaxLine Plus II 10k rpm SATA??? Is that a new drive coming out soon? Sounds like good competition for the WD Raptor if it is...
I was using HD Tach for my benchmark tests. The best I could pull out of my two Maxtor Diamond Max Plus 9 drives was around 24 MB/sec. That's with a stripe block size of 16k. Right now I have it in a RAID 1 because I think the one drive is dying. In this setup, HD Tach reports an average write speed of only 17 MB/sec with a max of only 20 MB/sec. The drives do about 20 MB/sec average and 23 MB/sec on their own. I would think that if they can do an average of 20 MB/sec on their own, they should at least be able to hit 30 MB/sec in RAID 0. If I can get them cleared again, I'd like to hook them up to my RAID controller over here on this computer (Gigabyte K8N Pro) and see if this ATA133 RAID controller is any better for them.
March 7th, 2004, 10:37 PM
I think all the Maxtor drives are the same in the previous graph.
I downloaded HD Tach and they are not offering any registration till vs 3.0 come out so I could not run any write test.
As for the poor results on the dying drive. . . that will corrupt the performance. Run the Max Blast utility and see what it says about the drive health.
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