SCSI 15000 versus 2x10000 SATA on RAID 0?

[gazzer82]

Hello

I am looking at building a new Catalyst system with a Mac Pro and am trying to work out whether it is better to go for the traditional SCSI system we normally use or to take advantage of the SATAII interface in the mac pro and use two 10000rpm 150GB SATAII drives in a Raid0 configuration to get 300GB 20000rpm drive access for a considerably reduced cost.

Has anyone tried this/got any experience with it??

Cheers

Gareth

[Gian]

Hello,... We have some MacPros, and we use the inside interface from the Macs with 3 x 250 Gb SATA II RAID 0. We are pretty happy with them.
I do not know your experiences with the SCSI systems, but we here did not had very luckly, so I have no comparasion for that.
What I can say is we can achive to play with NO frame loss 30fps in our case, up to at least....

1 mov with 2400 x 800 PhotoJpeg 75%
or
1 mov with 1024 x 768 PhotoJpeg Uncompressed

2 mov with 1024 x 768 PhotoJpeg 75%

4 DV movs from the original Cat Library.

I am conservative in that, and of course depends a lot of the movie, and other factors. I do not know what you can achive with the SCSI, but for us here is doing the job, and is cheapper and easier to work than the SCSIs.

[gazzer82]

Cheers Gian thats really good to know.

Anyone else here driven a system like that any harder? Be interested to know how far it could be pushed before it started dropping frames?

Cheers

Gareth

[tharding]

It is all about access time not spindle speed and besides 2 x 10000 rpm does not equal 20000 rpm total. Scsi still has fast seek times which is why playback can be better. The disk is able to randomly access the data faster. Remember that unlike a non linear editing system the Mac has no way of knowing what you want it to do next with Catalyst. So it is really depends on how fast the system can get to any piece of data with no notice.

A RAIDs real advantage is its ability to capture or play out a wide bandwidth of data in one hit. You need the balance of both with Catalyst or any media server. A single high speed SCSI drive tends to have that balance.

If you look back through the forum you will see a lot of posts about this including some speed tests that Richard did some time ago.

Personally I use an Xserve RAID which uses some really heavy handed caching in its onboard RAM to give really consistent playback of many layers. Prior to that I used Raptors set up in 4 drive raids.

Obviously it is all about what you can afford and what level of performance you need.

Have a bit of a read on the Barefeats.com and Macgurus.com websites where they explain both technologies fairly well.

Cheers

Toby

[samsc]

Cheers Gian thats really good to know.

Anyone else here driven a system like that any harder? Be interested to know how far it could be pushed before it started dropping frames?

Cheers

Gareth

sata drives tend to work horribly when you need lots of layers- doesnt matter what raid you use. raids dont help.

a single scsi 15000rpm will work so much better for most normal uses.

you will be dissapointed with how your 'raid' works.

[samsc]

Hello,... We have some MacPros, and we use the inside interface from the Macs with 3 x 250 Gb SATA II RAID 0. We are pretty happy with them.
I do not know your experiences with the SCSI systems, but we here did not had very luckly, so I have no comparasion for that.
What I can say is we can achive to play with NO frame loss 30fps in our case, up to at least....

1 mov with 2400 x 800 PhotoJpeg 75%
or
1 mov with 1024 x 768 PhotoJpeg Uncompressed

2 mov with 1024 x 768 PhotoJpeg 75%

4 DV movs from the original Cat Library.

I am conservative in that, and of course depends a lot of the movie, and other factors. I do not know what you can achive with the SCSI, but for us here is doing the job, and is cheapper and easier to work than the SCSIs.

ah but you see gian - you can only play back 4 dv movies from your raid- that is pretty typical.
and not very good. you would do a lot better with a scsi drive-

from a scsi drive you can do 6- 8 layers. because the access time is much faster- for most applications this is what people need.

also dont use 75% photojpeg you need to use 50-60% - believe me - the performance of photojpeg above 70% drops by 30% per layer - for no increase in anything. dont do it.
keep it below 75% at all times.


richard

[samsc]

Hello,... We have some MacPros, and we use the inside interface from the Macs with 3 x 250 Gb SATA II RAID 0. We are pretty happy with them.

1 mov with 2400 x 800 PhotoJpeg 75%
or
1 mov with 1024 x 768 PhotoJpeg Uncompressed

2 mov with 1024 x 768 PhotoJpeg 75%

4 DV movs from the original Cat Library.

gian - please can you do a little test-

remove raid - just work with 1 drive - and give us the result of your movie tests

[gazzer82]

Hello

Just thought i would fill you in on my findings.

I have tried a setup using a Mac Pro, Dual Quad 3.0Ghz, 4GB RAM, with an ATI Radeon X1900XT, outputting the video at 1024x768 on DVI to a second display.

I have then setup two video drives,

1 - 150GB 15000rpm SCSI Drive
2 - 2x150GB 10000rpm SATA Drive, In Raid 1 (Mirrored)

I am using the latest release of Catalyst, and all the current updates from Apple.

All test conducted with DV footage, motion JPEG to follow

Results:
SCSI
DV at 720x576 - 5 Layers till frames dropped
DV at 1024x768 - 4 Layers till frames dropped

SATA
DV at 720x576 - 5 Layers till frames dropped
DV at 1024x768 - 4 Layers till frames dropped

This is with no processing and playing full screen, not that it matters as teh CPU never went above 20%.

Cheers

Gareth

[samsc]

All test conducted with DV footage, motion JPEG to follow

Results:
SCSI
DV at 720x576 - 5 Layers till frames dropped
DV at 1024x768 - 4 Layers till frames dropped

gareth-

dv doesnt work at 1024x768 - you can create the movies but it doesnt work- all quicktime does is resize a 720x576 movie. DV is both fixed size and fixed bit rate.

---

did you install the latest version of the atto scsi drivers - the ones on any cd didnt work last time i tried?

http://www.attotech.com/software/drivers.html

its shown as version 4.1 on the UL5D driver page.
you will need to login and create an account - if you havent.

if you didnt you need to as the default driver has very poor performance.

[gazzer82]

Hi Richard

Yes i do have the latest drivers from atto installed, and just to add some more detail, the SCSi drive is a Fujitsu MAX3073NP, and the SATA drives are the Western Digital Raptors WD1500ADFD.

I can't believe i never new that about DV, doh, i am just about to encode the same video footage as Motion JPEG at 60% and see how they compare.

Cheers

Gareth