SATA RAID Disk Speeds – Is this correct???

[Kaspar Kallas]

yes they seem belivable for a begining of a disk

-Kaspar

[Bob Zelin]

you will find that you have more than enough to do 8 and 10 bit SDI uncompressed, and DVCProHD, but not enough for uncompressed HD, with your configuration.

Bob Zelin

[Mrvideo]

Go over to the AJA.com web site and they have their speed test software for FREE!

I have a 4 x 500 GB SATA RAID 0 in a G5 Quad and about 60-65 MB/sec per stripe is average.

Also check out the graphs on both http://www.barefeats.com and http://www.maxupgrades.com for approximate speed expectations of a 4 stripe SATA RAID.

[Bob Zelin]

If Mr. Video is only getting 60-65 mb/sec with AJA Kona System Test, then Mr. Video is doing something VERY WRONG, because a SINGLE SATA DRIVE will give you over 65mb/sec. 4 SATAs stripped RAID 0 will do dramatically faster than this (close to 200mb/sec).

I can only suspect that Mr. Video has not properly RAIDed his drives together, and is observing the speed of one single SATA drive, based on his results.

Bob Zelin

[Rx2_007]

Hi,

Well I wonder what MrVideo is quoting????….. because if you look at the break down of my stats I am getting 65MB/s with Random Reads… Only with buffered or sequential reads I am getting 445/202?

Benchmark Breakdown
Buffered Read : 445 MB/s
Sequential Read : 202 MB/s
Random Read : 65 MB/s
Buffered Write : 395 MB/s
Sequential Write : 225 MB/s
Random Write : 105 MB/s
Average Access Time : 10 ms (estimated)

I wonder what figures people quote most often?? because they vary considerabley?

Cheers

Robert

[Bob Zelin]

hi robert –
you are getting write speeds of 225mb/sec, and read speeds of 202 mb/sec. This is what I care about. Although I usually observe the write speed to be SLOWER than the read speed, this is damn good for 4 drives at RAID 0, and if you add more drives (with a card that can handle more drives), you will get performance that will allow you to do uncompressed HD at 1080i. I have no idea of what “buffered read and write” mean, or what they reflect.

Bob Zelin

[Kaspar Kallas]

But then again I HAVE DONE 10 BIT UC @ 1080 50i for more than two years on this setup – yes it has been short features and ad’s only because I had 300 GB drives – the biggest at the time of purchace
That gives you about 1TB of usable space that is faster than 160MB/s (10 bit 1080 50i is around 140MB/s – just a little overhead)

THIS IS VERY SHOESTRING BUDGET WAY TO DO IT BUT IT IS POSSIBLE

thing to consider, when you do not have the budget, is backup because most likley you are capturing straight from camera (on location) on HDCAM SR deck (not that cheap to rent) to make a good use of 10bit (if you use HDCAM, DVCproHD or HDV as source then you can capture 8 bit)
My backup solution was a PC computer with linux and rocketraid running 6 disk raid5 as offline backup (backup was done weekly over gigE) nowadays you might use external FW disk or even have two sata stripe raids mirrored

good luck
-Kaspar

[Mrvideo]

“”and about 60-65 MB/sec per stripe is average.””

Might help to read the whole thing before telling MrVideo that his RAID isn’t working well. Or maybe Bob Zelin doesn’t understand what a RAID stripe is?